delivered the Opinion of the Court.
In People v. McCoy, 832 P.2d 1043 (Colo.App.1992), the Colorado Court of Appeals reversed the conviction of defendant Vincent T. McCoy for two counts of aggravated robbery1 and one count of crime of violence.2 The court of appeals based its reversal on the conclusion that the trial court had erred in ruling that there was probable cause to support the arrest of the defendant without a warrant and in consequently denying the defendant’s motion to suppress evidence seized as a result of that arrest. We granted cer-tiorari to determine whether probable cause to arrest requires specific information that a particular crime has been committed by the suspect. Although we hold that such specific information is not an essential ingredient of probable cause to support a warrantless arrest, our evaluation of the totality of the circumstances in the present case causes us to conclude that the arresting officers lacked probable cause to arrest the defendant. We therefore affirm the judgment of the court of appeals.
I.
The facts in this ease are basically undisputed. On February 2, 1987, a Denver jewelry store was robbed at gunpoint. The robber took between 100 and 130 pieces of jewelry worth approximately $130,000.
On February 18, 1987, Sergeant Addison Thompson of the New Orleans, Louisiana, police department received a telephone call from a previously reliable informant who had more than forty years experience in the gold business.3 The informant said that a short, stout, black male about twenty-five years old had approached him that day in the central business district of New Orleans and offered to sell him five pieces of jewelry at much less than its obvious value. The informant described the jewelry and estimated its value at between $25,000 and $30,000. The sergeant related the information to Detective Steven Gaudet of the New Orleans police department. At the time Gaudet received this information, the New Orleans police had no knowledge of the Denver robbery.
During the afternoon of the following day, Sergeant Charles Miller of the New Orleans police department received a telephone call from a person who identified himself by name4 and as an employee of a particular jewelry store located in the central business district of New Orleans. The caller said that two persons had been in the store with a large amount of what appeared to be very expensive jewelry, trying to sell it at a very low price.5 The caller said that the store is a retail outlet and not a pawnshop, that it is rare for anyone to try to sell jewelry to the store in such a manner, that most of the persons who enter the store are regular customers, and that he had never seen these two individuals before. The caller said that these *1234circumstances aroused his suspicions. He then described the pair as a male and a female, both black, and said that the male was rather stocky and about twenty-five years old. The caller related that the male was wearing a black jacket with the name “McCoy” on it and a red devil on the back and that he was wearing a large amount of jewelry and carrying a little bag. The caller estimated the female was in her twenties and said she was wearing a red jacket. The caller also reported that the two individuals initially were standing outside the store while the telephone conversation was taking place and that as he spoke they walked down the block towards a nearby Burger King and passed out of sight. Sergeant Miller radioed for assistance and broadcast over police radio the information he had received from the jewelry store employee.
Detective Gaudet overheard the broadcast and was also aware of the information the police had received from the informant’s call of the previous day. Based upon the description given by the informant and the employee, Gaudet, accompanied by other officers, located and readily identified McCoy and his companion at the Burger King and promptly advised them that they were under arrest for investigation of possession of stolen property. The prosecution stipulated that the pair were arrested at the moment the police contacted them. In searching McCoy incident to the arrest, the police discovered a large amount of expensive jewelry. In a written statement, McCoy’s companion stated that McCoy told her that he had robbed a jewelry store in Denver. Acting pursuant to a search warrant, the police later discovered additional jewelry and a handgun in the motel room where McCoy and his companion were staying.
McCoy was returned to Denver and was convicted of two counts of aggravated robbery and one count of crime of violence following a jury trial in Denver District Court. Prior to trial, McCoy filed a motion to suppress the evidence found on him and at the motel on the ground that the police lacked probable cause to arrest him without a warrant. The trial court found both the informant and the jewelry store employee reliable,6 held there was probable cause to arrest, and denied the motion. On appeal, the court of appeals concluded that McCoy’s arrest was not supported by probable cause and that the evidence derived from the arrest was therefore improperly received at trial. The court determined that the error was not harmless and accordingly reversed the trial coui't’s judgment and remanded the case for a new trial.7 McCoy, 832 P.2d at 1046—47.
II.
We first consider the issue on which we granted certiorari; whether an arresting officer must possess specific information that a particular crime has been committed by the *1235suspect in order to effectuate a valid war-rantless arrest. The general principles concerning the validity of warrantless arrests are well settled and guide our analysis.
A.
Both the United States Constitution and the Colorado Constitution guarantee the right of the people to be secure in their persons against unreasonable seizures. U.S. Const, amends. IV, XIV; Colo. Const, art. II, sec 7. To effectuate these guarantees, police must have probable cause to arrest before they can subject a person to those deprivations of liberty that result from being arrested. Gerstein v. Pugh, 420 U.S. 103, 111-12, 95 S.Ct. 854, 862, 43 L.Ed.2d 54 (1975) (“The standard for arrest is probable cause.... ”); People v. Wolf, 635 P.2d 213, 217 (1981) (“Probable cause measures the constitutionality of an arrest by law enforcement officers.”). The probable cause standard “represents a necessary accommodation between the individual’s right to liberty and the State’s duty to control crime.” Gerstein, 420 U.S. at 112, 95 S.Ct. at 862; accord People v. Rayford, 725 P.2d 1142, 1146 (Colo.1986).
“ ‘Probable cause to arrest exists when the objective facts and circumstances available to a reasonably cautious officer warrant the belief that an offense has been or is being committed by the person arrested.’ ” People v. Alexander, 797 P.2d 1250, 1253-54 (Colo.1990) (quoting People v. Freeman, 668 P.2d 1371, 1377 (Colo.1983)); accord Beck v. Ohio, 379 U.S. 89, 91, 85 S.Ct. 223, 225-26, 13 L.Ed.2d 142 (1964); Brinegar v. United States, 338 U.S. 160, 175-76, 69 S.Ct. 1302, 1310-11, 93 L.Ed. 1879 (1949). That is, probable cause to arrest requires that at the time an arrest is made the police have probable cause to believe a crime has been or is being committed and probable cause to believe the person to be arrested' has committed or is committing the crime. “In determining whether there is probable cause to arrest, the totality of facts and circumstances known to the officer at the time of the arrest must be considered.” People v. Diaz, 793 P.2d 1181, 1183 (Colo.1990); accord People v. Florez, 680 P.2d 219, 225 (Colo.1984). Due consideration must be given to a law enforcement officer’s training and experience in determining the significance of the officer’s observations for this purpose. People v. Ratcliff, 778 P.2d 1371, 1375 (Colo.1989); see People v. Melgosa, 753 P.2d 221, 225 (Colo.1988). The probable cause standard is a practical, nontechnical conception and is to be measured by reasonableness, not mathematical probability. People v. Rayford, 725 P.2d at 1146. Mere suspicion, falling short of probable cause, is not sufficient to justify a warrantless arrest under constitutional standards. Wong Sun v. United States, 371 U.S. 471, 479, 83 S.Ct. 407, 412-13, 9 L.Ed.2d 441 (1963); People v. Saars, 196 Colo. 294, 298, 584 P.2d 622, 625 (1978). “The burden of proof is on the prosecution to establish the existence of probable cause to support a warrantless arrest.” Diaz, 793 P.2d at 1183.
B.
It is true that when assessing the totality of facts and circumstances to determine whether probable cause to arrest exists, an officer must consider any specific available information that a particular crime has been committed. However, lack of such information does not preclude a warrantless arrest if other facts known to the arresting officer warrant a belief that an offense has been or is being committed by the person to be arrested. United States v. Thevis, 469 F.Supp. 490, 504 (D.Conn.), aff'd, 614 F.2d 1293 (2d Cir.1979), cert. denied, 446 U.S. 908, 100 S.Ct. 1834, 64 L.Ed.2d 260 (1980) (“The fact that the officers could not say with certainty which particular crime had been committed or in fact that any crime had been committed does not mandate a finding of no probable cause.”); Campbell v. United States, 273 A.2d 252, 254 (D.C.1971) (knowledge of the commission of a particular crime is not an essential element of probable cause to arrest); State v. Simms, 571 So.2d 145, 149 (La.1990) (“It is not a prerequisite for the existence of probable cause that the po*1236lice know at the time of the arrest that a particular crime has definitely been committed.”); Commonwealth v. Ellsworth, 421 Pa. 169, 218 A.2d 249, 255 (1966) (probable cause may exist in the absence of knowledge of a particular crime); Stinson v. State, 578 S.W.2d 667, 668 (Tenn.Crim.App.1978) (the lack of knowledge of either the crime committed or the identity of the victim does not render the arrest illegal); see United States v. Portillo, 633 F.2d 1313, 1324 (9th Cir.1980) (warrantless arrest was supported by probable cause “even though no felony had been committed by [the suspect], or in fact, by anyone.”); United States v. Zimple, 318 F.2d 676, 679 (7th Cir.1963) (warrantless arrest upheld based on observation of conduct that supported reasonable belief that suspect had committed burglaries); see also 2 Wayne R. LaFave, Search and Seizure, § 3.6(a) (2d ed. 1987) (“[I]t is not essential to a finding of probable cause that the officer be able to relate the person [to be arrested] or property [in the person’s possession] to some particular prior crime.”). To hold otherwise would preclude police from making warrantless arrests when confronted by circumstances that overwhelmingly indicate that a crime has occurred. Such a result would not “give fair leeway for enforcing the law in the community’s protection.” Brinegar, 338 U.S. at 176, 69 S.Ct. at 1311.
In the present case, the court of appeals, citing People v. Quintero, 657 P.2d 948 (Colo.), cert. granted, 463 U.S. 1206, 103 S.Ct. 3535, 77 L.Ed.2d 1386, and cert. dismissed, 464 U.S. 1014, 104 S.Ct. 543, 78 L.Ed.2d 719 (1983), stated that “if the police have no information that a crime has, in fact, been committed, probable cause for an arrest does not exist.” McCoy, 832 P.2d at 1045. This statement reflects a misreading of Quintero.8
In Quintero, we affirmed the ruling of the trial court suppressing evidence obtained as a result of a warrantless arrest. Quintero. 657 P.2d at 951. Quintero was arrested while standing at a street corner bus stop. At his side were a television set and a video game, which he had covered with his shirt. The arresting officer heard a police radio dispatch, initiated by a call from a citizen, indicating only that a possible burglary suspect-was at that corner. The officer approached Quintero, asked him for identification, and learned that he had none. Quintero said that he had bought the television from someone in the neighborhood for $100 and was trying to go home with it. The officer, who had been joined by other police officers and by the citizen who made the initial report, then arrested Quintero. It was approximately five hours later before the police learned that the television set and video game were taken in a burglary. In upholding the suppression order we noted that the police knew that Quintero was a stranger to the neighborhood, that he claimed to have purchased a television set from someone in the neighborhood, that he had attempted to cover the television set and video game with his shirt, and that he had no identification. We also observed that “no evidence existed to establish that a crime had been committed.” We then stated that “[suspicion does not amount to probable cause” and concluded that probable cause was lacking to support the arrest. Id. at 950.
Quintero did not establish a principle that specific information that a particular crime has been committed is essential to probable cause. Properly understood, Quintero is simply an application of the totality of the circumstances test to particular facts.
Neither did our decision in People v. Schreyer, 640 P.2d 1147 (Colo.1982), cited by the court of appeals, require that police have specific information that a particular crime has been committed in order to establish *1237probable cause for a warrantless arrest. Schreyer involved the arrest of a suspect who had been the subject of a report by citizens that a person had been seen walking around cars in a residential neighborhood at an early morning hour, placing some items in the trunk of a car, and driving away. In ruling that probable cause for a warrantless arrest was lacking, we noted that the police were unaware that any crime had been committed. Schreyer, 640 P.2d at 1150. We did not thereby imply that police must necessarily possess such information to meet the probable cause requirement. Schreyer is simply another case in which absence of information that a particular crime had been committed was one factor in evaluating the totality of the circumstances leading to our conclusion that “the objective facts known to the officer at the time the defendant was arrested did not amount to probable cause.” Id. at 1150-51.
Accordingly, we hold that probable cause for a warrantless arrest does not require specific information that a particular crime has been committed.9
III.
We next consider whether the New Orleans police had probable cause to arrest McCoy.10 This requires that we determine whether there was probable cause to believe that a crime had been or was being committed and probable cause to believe that McCoy had committed or was committing it.
The police had probable cause to believe that the person who offered the jewelry at the jewelry store was the same person they located at Burger King and identified as McCoy. The specificity of the description given by the jewelry store employee, the information concerning the direction McCoy and his companion were walking, and the prompt arrival of the police at Burger King after receiving that information11 provided ample probable cause to believe that the man they located there, who matched the jewelry store employee’s description,12 was the same person who had tried to sell jewelry at the store. Whether there was probable cause to believe that the person who tried to sell five items of jewelry to an informant a day earlier was the same person arrested at Burger King is much more problematic because of the generality of the description of the person who offered the jewelry on the former occasion and the absence of information indicating 'that any of the same jewelry was *1238offered on both occasions. Assuming for the purpose of argument that there was probable cause to believe that McCoy was the person who had engaged in the suspicious activity on both occasions, the critical issue becomes whether the information concerning his activities constituted probable cause to believe that he had committed or was committing a crime.13
Neither the defendant’s physical characteristics nor his attire contributes to a conclusion that a crime had been or was being committed. It is his offer of jewelry for sale at greatly reduced prices under the circumstances outlined above that provides the only basis to suspect the commission of a crime. Certainly there are innocent reasons why a person might find it necessary to sell items of personal jewelry at greatly reduced prices. In the second incident, the defendant walked into an established jewelry store where he was not known and offered to sell jewelry. The incident took place in the afternoon. The defendant wore a jacket on which his name was displayed and also wore a large amount of jewelry. The very openness of the offer tends to undermine the suspicion that the jewelry was stolen. Cf. United States v. Welker, 689 F.2d 167 (10th Cir.1982) (where Spanish-American arrestee removed an envelope from an apartment mailbox in broad daylight and without acting furtively in a neighborhood the arresting officer considered to be black, and could produce no identification on request, the officer lacked probable cause to arrest). The arresting officer himself, as a basis for the arrest, informed McCoy that he was under arrest for investigation of possession of stolen property, suggesting a lack of probable cause for the arrest.
The determination of when facts cross the line from reasonable suspicion to probable cause is difficult. “That line necessarily must be drawn by an act of judgment formed in the light of the particular situation and with account taken of all the circumstances.” Brinegar, 338 U.S. at 176, 69 S.Ct. at 1311; see generally 2 Wayne R. LaFave, Search and Seizure, § 3.6(a) (2d ed. 1987). Giving due regard to the competing personal liberty and crime control interests at stake, and considering the totality of the circumstances, one of which is the absence of knowledge of a crime, we hold that the facts here give rise to reasonable suspicion but fall short of establishing probable cause to believe a crime had been or was being committed by McCoy when he was arrested.
We therefore affirm the judgment of the court of appeals.
SCOTT, J., specially concurs. ROVIRA, C.J., dissents, and VOLLACK and MULLARKEY, JJ., join in the dissent.. § 18-4-302, 8B C.R.S. (1986).
. § 16-11-309, 8A C.R.S. (1986).
. Evidence was presented that as a result of information from this informant a murder case in Texas had been "cleared” but was still pending, at least two convictions had been obtained on New Orleans rape cases, and the suspect in the murder case had been convicted of possession of stolen property. The officer who had been contacted by the informant said that he had never received unreliable or bad information from the informant. The trial court in ruling on the defendant’s motion to suppress found the informant to have been "previously reliable.”
. At the suppression hearing, Sergeant Miller was unable to remember the name of the employee.
. The police had no specific information on the quantity or description of the jewehy offered on this occasion, nor were they told the price at which jewelry was offered for sale on this occasion or the earlier one.
. The trial court found that the person who reported the February 18 incident to Sergeant Thompson was reliable based in part on his history of supplying reliable information to police officers on prior occasions. See note 3, supra. Reliability of a confidential informant can be supported by showing that the informant in the past has supplied information that proved reliable. People v. Arellano, 791 P.2d 1135, 1139 (Colo.1990); People v. Varrieur, 771 P.2d 895, 898 (Colo.1989); see Draper v. United States, 358 U.S. 307, 313, 79 S.Ct. 329, 333, 3 L.Ed.2d 327 (1959); People v. Martinez, 173 Colo. 17, 21, 475 P.2d 340, 342 (1970). The court considered the jewelry store employee to be a citizen informant and found him reliable on that basis. When the source of information is an identified citizen informant with first hand knowledge of the incident reported, such information is sufficiently reliable to be utilized in determining the existence of probable cause. People v. Donnelly, 691 P.2d 747, 749 (Colo.1984). In such circumstances the prosecution is not required to establish either the credibility of the citizen or the reliability of the information. People v. Pate, 705 P.2d 519, 521 (Colo.1985); People v. Henry, 631 P.2d 1122, 1127 (Colo.1981).
. The court of appeals held that on retrial before admitting any evidence discovered at the hotel room, the court must address whether such evidence was obtained as the fruit of the unconstitutional arrest of McCoy and is therefore inadmissible. McCoy, 832 P.2d at 1046-47. See, e.g., Wong Sun v. United States, 371 U.S. 471, 488, 83 S.Ct. 407, 417-18, 9 L.Ed.2d 441 (1963); People v. Madson, 638 P.2d 18, 33 (Colo.1981).
. It is not entirely clear from the court of appeals’ opinion whether this was the standard applied. There is language later in the opinion that suggests that the arresting officers need have possessed only "information that allowed them to form a reasonable belief that a crime had actually been committed,” McCoy, 832 P.2d at 1046, a formulation consistent with the totality of the circumstances test. Consistent also with this latter test is the court of appeals’ statement that probable cause was lacking because of the absence of information other than the attempt to sell jewelry at a price substantially below its fair market value "from which it may reasonably be inferred that the jewelry is illegally in the seller’s possession.” Id.
. Some courts have stated that when the police do not have specific information that a particular crime has been committed, more and better evidence is needed to prove that probable cause exists to support an arrest without a warrant. State v. Johnson, 363 So.2d 684, 689 (La.1978); State v. Frazier, 421 A.2d 546, 550 (R.I.1980); see also 1 Wayne R. LaFave, Search and Seizure, § 3.2(e) at 596-97 (2d ed. 1987). As the Supreme Court of Illinois put it, "[w]here there is uncertainty as to whether a crime has been committed, the privacy rights may be given more consideration [in striking the balance between interests of privacy and law enforcement].” People v. Wright, 111 Ill.2d 128, 95 Ill.Dec. 787, 793, 490 N.E.2d 640, 646 (1986). We are confident that our totality of the circumstances test adequately includes these concepts, which are simply ways of noting the importance of knowledge that a crime has been committed as a factor in determining probable cause.
. Because the prosecution stipulated, and the trial court determined, that McCoy was arrested immediately upon contact by the police, none of the officers’ actions can be justified as based on a permissible investigatory stop supported by reasonable suspicion. See, e.g., Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968); People v. Lingo, 806 P.2d 949, 952 (Colo.1991); Stone v. People, 174 Colo. 504, 485 P.2d 495 (1971). The prosecution does not contend that the seizure can be supported on that basis.
. "An officer who does not personally possess sufficient information to constitute probable cause may nevertheless make a valid arrest if he acts upon the direction or as a result of a communication from a fellow officer, and the police, as a whole, possess sufficient information to constitute probable cause.” People v. Freeman, 668 P.2d 1371, 1377 (Colo.1983); accord, e.g., People v. Alexander, 797 P.2d at 1254. This is commonly referred to as the fellow officer rule.
. Although the trial court found that the arresting officer “recognized that the defendant was wearing jewelry, including a large rope chain and other items of jewelry,” it is clear from the record that the officer did not see this jewelry until he had arrested McCoy. In light of all the other identifying characteristics reported to the officers, we do not regard this discrepancy as significant.
. Possession of stolen property is a crime in Louisiana, La.Rev.Stat.Ann. § 14:69 (West 1986), as it is in Colorado, §§ 18-4-401 and 18-4-410, 8B C.R.S. (1986 & 1993 Supp.).