OPINION
ON APPELLANT’S MOTION FOR REHEARING
ROBERTS, Judge.On original submission in this case, the majority affirmed on the basis that this was a conspiracy. A conspiracy was not pled, proven, or briefed in this case. It is axiomatic that before such exhibits could be admissible there must be proof that the act or declaration is, in fact, the work of a co-conspirator. 2 Branch’s Ann.P.C., Sec. 721-722.
That opinion primarily relied upon three cases to support its conspiracy theory. We have examined these cases and find the following:
In Phelps v. State, 462 S.W.2d 310 (Tex.Cr.App.1970), the evidence clearly showed a conspiracy. It was proven that the accused there conspired with others to obtain funds to purchase weapons through the Cuban Embassy in Canada. There was proof that the defendant discussed the robbery with others and planned it; the purpose of the robbery was clearly established, i. e., to buy guns in Canada. The robbery was rehearsed in a house owned by the defendant. In summary, such acts and declarations were obviously the product of a co-conspirator.
In the case of Parnell v. State, 170 Tex.Cr.R. 30, 339 S.W.2d 49 (1959), the offense charged was embezzlement. Again, there was evidence showing a conspiracy by the promoters of a certain stock. In addition, the jury was charged on the law of conspiracy, as well as on the law of principals.
In the third case relied upon, Saddler v. State, 167 Tex.Cr.R. 309, 320 S.W.2d 146 (1959), the evidence clearly showed accused and another person acting together, in the unlawful sale of marihuana, and there was accomplice witness testimony to this effect.
The conclusion reached in the original opinion is a unique one — that on appeal, and it being mentioned for the very first time, a theory of conspiracy may be developed, not by the prosecuting authorities, but by this Court, and a decision affirmed on that basis. In the cases cited, the evidence of the conspiracy is unquestioned. In the instant case, it is highly doubtful that we should even reach that question since there is not even an affirmative link shown between the “declarations” in the notebooks and the appellant. The fact re*175mains that these exhibits were never authenticated as the product of a co-conspirator. Surely, this Court cannot infer that essential element. But that is what occurred on original submission.
In order to answer other arguments upon which the original opinion relied, the following facts are necessary.
The evidence reflects that on September 16, 1970, four officers of the Austin Police Department executed a search warrant at a house located in the City of Austin. Three of the officers entered the house together, while one of the officers remained outside until called by one of the officers who entered. The officers entered into a living-room and passed through it to the front bedroom. In the front bedroom they saw a man, later identified as Arnold Neal, asleep on a couch. One of the officers remained in the front room while the two other officers proceeded to the back bedroom. In the back bedroom, the officers found appellant and a woman, Faubian,1 seated at a table upon which was a plate containing 39 capsules of heroin and various items of narcotic paraphernalia. As a result of a further search of the premises conducted by the officers, a "barracks bag” was found in a closet which was located in the kitchen of the house, immediately adjacent to the back bedroom. The bag contained a quantity of marihuana and three notebooks which contained written entries which appeared to be records of narcotics transactions. In a closet located in the front bedroom, a plate was found on which was a quantity of heroin and two hypodermic syringes. A group of papers which appeared to be records of narcotics transactions was also found in the closet.
Appellant raised eighteen grounds of error in his brief. In his second through eleventh grounds of error, he complained of the admission into evidence of the notebooks which were found in the closet adjacent to the bedroom where appellant and Faubian were seated.
The record reflects that the three notebooks in question were of the small spiral-binder type. They appear to be a record of personal expenditures by and money owing to the person to whom the books belong. Many of the entries are of a personal nature, such as “groceries $35.00.” Others consist of a large number of given names, without surnames, followed by amounts of money, such as “Rooster $30.-00.” In addition, there are a number of entries which appear to be in the nature of an inventory. For example, at several places in the books the heading “Assets” appears, followed by notations such as “Lds,” “Gms Hsh,” “Hsh,” each of which is followed by an amount and an entry designated “cash value.” One page bears the designation “Sales” and consists of a list of dates, each followed by a designation such as “7 gms Hsh” and an amount of money. The column of money is designated “Cash Profits.” At several places in the books the headings or notations “Plds Sold,” “Lds Sold,” “Pills Sold,” “One G,” “Pills Left” etc., appear. One of the officers testified that the term “hash” referred to hashish, and that the term “lid” meant a one ounce package of marihuana, and that the term “G” referred to a gram of either heroin or marihuana. Appellant’s name does not appear in the books, although the name “Ron” appears in several places, usually under the heading “Assets.” Also, the name Arnold appears in several places such as in notations “Arnold’s Money” and “I owe Arnold $80.00.”
The papers which were found in the front bedroom included a University of Texas at Austin registration card, a business reply card addressed to a clothing firm, and a United States Post Office change of address card, all of which bore the name Arnold Neal (the man who was found asleep in the front bedroom) and the address of the house where the items were found. The notations on the papers were similar to those which were found in the notebooks.
*176Appellant objected to the admission of the notebooks on several grounds, but did not object to the admission of the papers found in the front bedroom, apparently because the items found with the papers connected them with Neal. This was part of appellant’s defensive theory, i. e., that the narcotics belonged to Neal.
Appellant contended that the papers were inadmissible for several reasons, including that (1) they were not shown to have been written by him or that they belonged to him, (2) that they were irrelevant in a prosecution for unlawful possession of narcotics, (3) that they were unduly prejudicial as tending to show sale of narcotics, an extraneous offense, (4) that they were hearsay and did not fall within an exception to the hearsay rule, (5) that the notebooks were not part of the “res gestae,” (6) that the content of the notebooks was not sufficiently identified and therefore the jury was allowed to speculate as to the meaning of the entries.
The record reflects that the court admitted the evidence “on the theory that they are part of the res gestae, and on the theory of co-principals charged in this case, as to guilt or innocence . . . . ”
The notebooks were improperly admitted. In light of the court’s statement, and in the face of appellant’s objection on the ground (among others) that the notebooks were hearsay, the notebooks were not admitted for the truth of the matter asserted therein, and therefore were not hearsay. Unless an out of court statement is offered for the truth of assertion contained therein, it is not hearsay. E.g., McCormick & Ray, Texas Law of Evidence, § 781; Brown v. State, 74 Tex.Cr.R. 356, 169 S.W. 437 (1913). However, an extra-judicial statement or writing may be admitted as circumstantial evidence from which an inference may be drawn, and not for the truth of the matter stated therein, without violating the hearsay rule. McCormick & Ray, supra, § 796. See Haynes v. State, 475 S.W.2d 739 (Tex.Cr.App.1972) ; Windham v. State, 169 Tex.Cr.R. 448, 335 S.W.2d 221 (1960). Therefore, assuming that the notebooks were so offered in the present case, the question which must be answered is “What was the inference to be drawn from the admission of the notebooks as circumstantial evidence?” It is obvious that the only inference to be drawn was that some person was dealing in narcotics and that the person was appellant. While it is possible that in order for such inference to be drawn it is necessary to consider the truth of the matters contained in the notebooks, we will assume, for the purpose of decision, that such inference can be drawn by considering the notebooks as circumstantial evidence only. We are therefore brought to the question of whether such an inference is relevant in a prosecution for possession of heroin and, if so, whether such evidence should be admitted or excluded as a matter of policy.
In a prosecution for possession of heroin, evidence that the accused has sold narcotics is evidence of an extraneous offense. While the general rule is that extraneous offenses are inadmissible as evidence of guilt, there are certain exceptions to the general rule, such as the exception that admits evidence of extraneous offenses to show knowledge. McCormick & Ray, supra, § 1521.
Knowledge (or criminal intent) is an essential element of the crime of possession of a narcotic drug. E.g., Ramos v. State, 478 S.W.2d 102 (Tex.Cr.App. 1972); Fawcett v. State, 137 Tex.Cr.R. 14, 127 S.W.2d 905 (1939). Therefore, evidence which tends to show knowledge is a relevant part of the State’s case in chief. Evidence that the accused has, in the past, sold the narcotic of which he is now alleged to have possession is of probative value in establishing knowledge. People v. MacArthur, 126 Cal.App.2d 232, 271 P.2d 914 (1954); Overton v. State, 78 Nev. 198, 370 P.2d 677 (1962). See generally, Gonzales v. State, 410 S.W.2d 435 (Tex.Cr.App.1966) *177App.1966) cert. denied 387 U.S. 925, 87 S.Ct. 2044, 18 L.Ed.2d 982. That such evidence shows another crime is not objectionable. Evidence which tends to prove any material fact in connection with the offense is admissible despite the fact that it also shows the commission of other offenses. McCormick & Ray, supra, § 1521; Gonzales v. State, 410 S.W.2d 435 (Tex.Cr.App. 1966).
In light of the danger of prejudice arising from the use of evidence of the sale of narcotics, we would add one restriction on the use of such evidence in possession cases. That is, such evidence should not he introduced as part of the State’s case in chief unless the case is based upon circumstantial evidence. Of course, in the technical sense, knowledge (or criminal intent), being an intangible, can only be proved by circumstantial evidence. By circumstantial evidence, however, we mean evidence from which knowledge cannot readily be inferred. For example, where the evidence shows that the accused was in the process of injecting a narcotic, or preparing it in a manner peculiar to that particular drug, then evidence of prior sales, while still relevant on the issue of knowledge, is not needed in order to prove the State’s case, and, in light of that fact, should not be admitted because the value of such evidence is then outweighed by its tendency to prejudice the jury.
Of course, the State should not be limited in its ability to offer evidence in rebuttal, as where the accused admits possession, but denied that he knew the substance was a narcotic. See People v. Howard, 150 Cal.App.2d 428, 310 P.2d 120 (1957).
That being the case, evidence of a prior sale by appellant would have been admissible to show knowledge. However, we are faced with the problem of determining whether the notebooks were competent evidence of a prior sale by appellant.
If the notebooks were offered for the truth of the matters stated therein, they are inadmissible as hearsay, unless they fall within an exception to the hearsay rule. If offered against appellant, in order to be admissible, proof of execution by him must first be shown. Tipton v. State, 125 Tex.Cr.R. 658, 69 S.W.2d 1111 (1934). In this case, no evidence was offered as to the execution of the notebooks.
Likewise, even if offered as circumstantial evidence only, some connection to appellant must be shown. Here, it was shown that appellant had executed a lease of the premises prior to the date in question, and that he was arrested in reasonably close proximity to the notebooks. In order to connect appellant to the notebooks, it is necessary to infer that he controlled or occupied the premises and, from that inference, to infer that the items in the closet were his. This connection is too remote, in light of the potential for undue prejudice contained in the evidence. Unlike the papers in the front bedroom, no link between the notebooks and another person was found. This case is therefore easily distinguishable from our recent holding in Phenix v. State, 488 S.W.2d 759 (Tex.Cr.App.1972). in Phenix, the accused was arrested in his garage apartment and a handwritten note was found on a desk. The note read:
“A. P. Fri.
“More on the way. I still owe you four lids worth. ‘Ill check with Dan on the 150 tomorrow.
C.P.”
Defendant’s full name was Robert Alan Phenix. Thus, an affirmative ownership link was established. This Court held that any error in admitting the note was harmless, in that there was an abundance of other evidence before the jury which suggested that Phenix was dealing in marihuana.
*178The State contended that the notebooks were admissible as part of the res gestae of the arrest. We disagree. It is true that evidence of tangible objects found during the course of a search is often admitted as “res gestae” as is evidence of various, seemingly irrelevant details of a transaction. This is permitted, even though the relevance of the evidence may not be readily apparent, because the law recognizes that transactions do not occur in a vacuum. By being informed of all the circumstances surrounding a particular transaction, the trier of fact is enabled to put the witness’s testimony in its proper perspective, and to form a basis for judging the credibility of the witness. Some transactions are such that the “bare bones” of the occurrence might seem quite plausible, but when related in context seem very unlikely to have actually occurred (or vice versa). Therefore, such evidence is usually admitted even though its relevance is not shown, or, even if irrelevant, unless it is unduly prejudicial. McCormick & Ray, supra, § 911. In this case, the notebooks not being admissible as evidence of a prior sale, if admissible at all, must be “res ges-tae.” However, due to their prejudicial. nature, it cannot be said that their admission would be harmless.
Appellant’s motion for rehearing is granted, and the judgment is reversed and the cause remanded.
. See Faubian v. State, 480 S.W.2d 194 (Tex.Cr.App.1972).