OPINION
STOWERS, Justice.We granted certiorari to determine whether the discovery of a roach clip with marijuana residue on it in the ashtray of defendant-respondent’s, Lucio Pena’s, vehicle gave the officers probable cause to search the interior of that vehicle.
The court of appeals in its opinion set forth the facts relevant to this inquiry as follows. On May 19, 1986, New Mexico State Police Officers Clifford Frisk and Norman Denton conducted a roadblock at U.S. Highway 62/180 and Marathon Road in Lea County, New Mexico. Pena's vehicle was stopped at the roadblock and, pursuant to Officer Frisk’s request, respondent produced a valid driver’s license, motor vehicle registration, and proof of insurance. Thereafter, Frisk asked Pena if he could look in the vehicle’s ashtray. Pena handed the ashtray to the officer who found a roach clip with residue on it among the coins therein. A field test revealed that the residue was marijuana. Pena was issued a non-traffic citation to appear in court.
Subsequently, Frisk searched the interior of the vehicle, including a brown paper sack. Pena objected to the search of the paper sack maintaining it was “personal.” Nonetheless, Officer Frisk opened the sack, which contained scales with cocaine residue, a jar with cocaine residue, and a number of empty small plastic bags.
Pena was immediately placed under arrest. A pat-down search at the scene revealed two packets of cocaine, a straw with cocaine residue, and $1,997.91 in cash. After the arrest, Frisk voided the non-traffic citation and transported Pena to New Mexico State Police headquarters. An inventory search of the vehicle, which was started at the scene, was completed at the police station. That search revealed twenty-six one-gram packets of cocaine in a tissue box.
Pena filed a motion to suppress all the evidence claiming it was obtained as a result of an unreasonable and illegal search without a search warrant. The motion was denied. The trial court found that “Officer Frisk, asked defendant if he could look in [the] ashtray and defendant gave [his] consent, removing the ashtray and handing it to Officer Frisk.” After a trial to the court, Pena was found guilty of trafficking a controlled substance, cocaine, by possession with intent to distribute, and possession of drug paraphernalia.
In a 2-1 decision, the court of appeals reversed the trial court and remanded the cause for a new trial. The appellate court held that although the search of the ashtray was valid based on Pena’s consent, the subsequent search of the paper bag and the evidence discovered thereafter did not fall within an exception to the warrant requirement. The dissent agreed with the majority “that defendant validly and voluntarily consented to a search of the ashtray wherein Officer ... Frisk discovered drug paraphernalia in the form of an alligator or roach clip.” It disagreed, however, with the conclusion that the discovery of the roach clip with residue that tested positive for marijuana did not provide probable cause to believe there was contraband inside Pena’s vehicle. We agree with the dissenting opinion that the residue of marijuana did provide probable cause to justify a warrantless search under the automobile exception to the warrant requirement. We reverse the court of appeals and affirm the trial court.
As stated in the court of appeals’ opinion, it has long been the rule that warrantless searches are per se unreasonable under the fourth amendment of the United States Constitution. See State v. Capps, 97 N.M. 453, 455, 641 P.2d 484, 486, cert. denied, 458 U.S. 1107, 102 S.Ct. 3486, 73 L.Ed.2d 1368 (1982); State v. Ruffino, 94 N.M. 500, 501, 612 P.2d 1311, 1312 (1980); see also N.M. Const, art. II, § 10. This rule is subject to few exceptions. One of the exceptions of the warrant requirement is the “automobile exception,” which arises when police officers have probable cause to believe there is contraband inside a vehicle stopped on the road. United States v. Lopez, 777 F.2d 543, 550 (10th Cir.1985); cf. State v. Sandoval, 92 N.M. 476, 478, 590 P.2d 175, 177 (Ct.App.1979) (exigent circumstances are not required for the search of a vehicle stopped on a public highway where there is probable cause for the search). Under the automobile exception, the police officer’s conduct in searching the interior of Pena’s vehicle was proper if it was supported by probable cause. At issue in this case is not the validity of the roadblock or the consensual search of the ashtray, but rather, whether the roach clip with its marijuana residue was sufficient to establish probable cause. The court of appeals opined that:
The probable cause requirement is satisfied when the officers conducting the search have “reasonable or probable cause” to believe that they will find the instrumentality of a crime or evidence pertaining to a crime before they begin their warrantless search. And, if after a valid investigatory stop, probable cause then arises, a search may be made. [Citations omitted.]
United States v. Matthews, 615 F.2d 1279, 1287 (10th Cir.1980). In other words, probable cause arises where the facts and circumstances warrant a prudent person in believing that an offense has been or is being committed. State v. Snedeker, 99 N.M. 286, 290, 657 P.2d 613, 617 (1982); see Beck v. Ohio, 379 U.S. 89, 85 S.Ct. 223, 13 L.Ed.2d 142 (1964). “More specifically, probable cause must be evaluated in relation to the circumstances as they would have appeared to a prudent, cautious and trained police officer.” Lopez, 777 F.2d at 551.
Applying these standards, the court of appeals reasoned that the observation of a roach clip did not establish probable cause for a search “[i]n the absence of evidence tending to show its recent use or its use by occupants of the car.” The appellate court then concluded that since “[t]he officer had no reason to believe that the roach clip had been used so recently that contraband might still be in the car,” the search of the car and paper sack could not be justified. The conclusion, as pointed out in the dissenting opinion, overlooked certain critical facts. It was the presence of narcotics material on the roach clip, and not merely the roach clip, that tied it to illegal use and gave rise to probable cause for the search.
As enunciated in the dissent, the court of appeals’ reliance on People v. Franklin, 46 A.D.2d 189, 362 N.Y.S.2d 34 (1974), is not dispositive of this case. In Franklin, which held the warrantless search unlawful, the police officer “observed ‘a roach clip’ on a key ring which the defendant produced from his pocket, and there was a ‘charred residue’ but no narcotic material on the end of the clip, which the officer knew from past experience was a type of instrument commonly used for smoking marijuana.” Franklin, at 190, 362 N.Y. S.2d at 35 (emphasis added). The dissent reasoned that “since clips can apparently be used for legitimate purposes, the New York [appellate] court correctly dismissed as insufficient the clip itself as providing probable cause, without ‘indication that the roach clip had recently been used for smoking marijuana by reason of its being hot or by the presence of smoke in the vehicle.’ ” The dissent concluded that in Franklin, “the court was simply saying that, without narcotics material, something more must be shown to tie the roach clip to illegal use, i.e., it being hot or warm from recent use or smoke in the car. That something more is present in the case before us.” Cf. People v. Jenkins, 77 A.D.2d 353, 432 N.Y.S.2d 956 (1980) (observation of a “hash pipe” with marjiuana residue provided probable cause to seize it and arrest defendant); State v. Durrell, 111 R.I. 582, 305 A.2d 104 (1973) (defendant’s possession of a brass pipe which the officer knew from his experience and training was used for the purpose of smoking marijuana provided probable cause to seize the evidence).
In the present case, Officer Frisk testified that the roach clip had a “brown loop kind of thing” which was consistent with what he knew from training and experience was used for smoking marijuana. The field test conducted on the residue tested positive for marijuana. Discovery of the marijuana on the roach clip provided the officers with probable cause to search the vehicle, including the brown paper bag. “If probable cause justifies the search of a lawfully stopped vehicle, it justifies the search of every part of the vehicle and its contents that may conceal the object of the search.” United States v. Ross, 456 U.S. 798, 825, 102 S.Ct. 2157, 2173, 72 L.Ed.2d 572 (1982); see also Capps, 97 N.M. at 457, 641 P.2d at 488 (officer making lawful warrantless search of automobile could search entire vehicle including containers to locate contraband).
We reverse the court of appeals and affirm the conviction by the trial court.
IT IS SO ORDERED.
SCARBOROUGH and BACA, JJ„ concur. RANSOM, J., specially concurs. SOSA, C.J., dissents.