The evidence reflects that Frank Marquez, a former heroin addict, contacted Sergeant Bobby Sides of the Austin Police Department in regard to making some undercover purchases of heroin for the police. As a result of the conversation, Marquez came to the Austin Police Station, where he was searched and given five dollars with which to make the purchase. Officer Sides and Marquez then left the police station in an automobile which had been specially prepared for undercover work. Marquez drove, and Officer Sides rode in the trunk, which had been outfitted with a radio for communication. In addition, several holes had been bored in the rear fenders of the car, and the taillight assembly had been removed so that the occupant of the trunk could see out. Sides and Marquez proceeded to a location on East Eleventh Street in the city of Austin, where the car stopped and Marquez got out and approached a group of people who were standing on the sidewalk and asked if he could buy some heroin. One member of the group, Bobby Guice, then signaled to appellant, who was located a short distance up the street in a car. The appellant then came to the location where Marquez and Guice were standing. Guice introduced Marquez to the appellant and told him that "He (appellant) is allright." Marquez then gave the five dollars to Guice, who gave it immediately to appellant. The appellant then handed the capsule of heroin to Marquez. Marquez returned to the car and drove away.
