Defendants were stopped for a citizenship check at the permanent checkpoint near Falfurrias, Texas. During the questioning, the Border Patrol officer noticed a suspicious configuration of the quilt covering the rear seat of their vehicle and detected the odor of marijuana. A search of the vehicle revealed approximately 200 pounds of marijuana in the back seat and trunk.

Stopping a vehicle at a permanent checkpoint to determine citizenship does not offend the Fourth Amendment. United States v. Martinez-Fuerte, 428 U.S. 543, 96 S.Ct. 3074, 49 L.Ed.2d 1116 (1976). The visual observations and odor detected gave the officer probable cause to search defendants’ car. United States v. Torres, 537 F.2d 1299 (5th Cir. 1976).

Defendants made incriminating statements after they had twice been advised of their constitutional rights, both in English and Spanish. See Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966). The district court conducted a hearing, pursuant to 18 U.S.C. § 3501 (1970), to determine the voluntariness of defendants’ statements and found that their statements were voluntary. Accordingly, the district court permitted testimony concerning the statements to be admitted as evidence to the jury. The jury was properly instructed on voluntariness as well as the applicability of 18 U.S.C. § 3501 (1970). The judgments of conviction and sentences appealed from are

AFFIRMED.