in the search. No other defendant has advanced a claim to even an arguable expectation of privacy in the house. See United States v. Salvucci, 448 U.S. 83, 100 S.Ct. 2547, 65 L.Ed.2d 619 (1980) (standing to challenge applies only to those whose own fourth amendment rights have been violated — legitimate expectation of privacy required); United States v. Tortorello, 533 F.2d 809 (2 Cir.), cert. denied, 429 U.S. 894, 97 S.Ct. 254, 50 L.Ed.2d 177 (1976).
IV.
Defendant Llanez-Diaz contends that there was insufficient evidence, both as to the conspiracy count and as to the substantive possession count, to sustain his conviction. We agree only as to the substantive count.
To justify a conviction on the substantive possession count under 21 U.S.C. §§ 841(a)(1) and 841(b)(6), the government was required to present evidence that Llanez-Diaz knowingly possessed the marijuana — that is, that he knowingly exercised or had the power to exercise dominion and control, either actual or constructive and either individually or jointly with others, over it.
See United States v. Laughman, 618 F.2d 1067, 1076-77 (4 Cir.),
cert. denied, 447 U.S. 925, 100 S.Ct. 3018, 65 L.Ed.2d 1117 (1980);
United States v. Stephenson, 474 F.2d 1353, 1355 (5 Cir.1973).
As we must, we have reviewed the evidence at trial in the light most favorable to the government. Glasser v. United States, 315 U.S. 60, 62 S.Ct. 457, 86 L.Ed. 680 (1942). At best, the government’s evidence tended to show that Llanez-Diaz was armed and that he was present in an automobile which escorted the U-Haul truck containing marijuana, and that the other occupant of the auto was Moisés Alvarez, a key conspiracy figure. However, LlanezDiaz was out of view of the U-Haul truck while the drug transaction was occurring. No surveillance agent placed him in the Mercedes while it was escorting the truck through Baltimore, a fact that is significant because the Mercedes stopped at the Sheraton before reaching the Hyatt, and thus may have discharged and picked up passengers at the Sheraton. Llanez-Diaz may also have been the subject of a photograph taken by federal agents of a group of men at Collazo’s house.
All of this, to our minds, offers no convincing reason to believe that Llanez-Diaz knew of the presence of the marijuana or exerted any dominion or control, actual or constructive, sufficient to indicate possession with intent to distribute. The situation here is different from the one with which we dealt in Laughman, supra, where the conviction of the skipper of a sailboat for possession of marijuana with intent to distribute was upheld. There, a great deal of drug-related activity (moving packages assumed to be marijuana around the boat) had been observed, which in turn supported the inference that the skipper must have been aware of and participated in the delivery. No such evidence exists here. In the present case the evidence is entirely consistent with the theory that Llanez-Diaz was brought along merely as a hired gun and was not made aware of what was taking place or accorded any role other than that of armed chauffeur to Moisés Alvarez.
We reject, however, the argument of Llanez-Diaz that there was insufficient evidence to sustain his conviction under 21 U.S.C. §§ 846 and 841(b)(6) for conspiracy to possess marijuana with intent to distribute. To sustain the conspiracy conviction, there need only be a showing that defendant knew of the conspiracy’s purpose and some action indicating his participation. Laughman, supra, 618 F.2d at 1075. These elements can be shown by circumstantial evidence such as his relationship with other members of the conspiracy, the length of this association, his attitude, conduct, and the nature of the conspiracy. In the circumstances of this case, the jury could have inferred that Llanez-Diaz was party to the ongoing purposes of the conspiracy to distribute large quantities of marijuana, even if the evidence was not clear on the exact nature of his participa