Passage: Two blocks from the crime scene, Officer Don Fouke, responding to the call, observed a white man, walking along the sidewalk and stepping onto a stairway leading up to the front yard of one of the homes on the north side of the street; the encounter lasted only five to ten seconds.Fouke estimated the man to be 35-to-45 years old, while the teenagers who observed the killer in Stine's cab mentioned he was a 25-to-30-year-old white male adult at about 5-foot-8-inch (1.73 m) to 5-foot-9-inch (1.75 m) tall. The radio dispatcher had alerted to be on the lookout for a black suspect, so they drove past him without stopping; the mix-up in descriptions remains unexplained. A search ensued, but no suspects were found. The three teen witnesses worked with a police artist to prepare a composite sketch of Stine's killer; a few days later, this police artist returned, working with the witnesses to prepare a second composite sketch of the killer.

Question: How many teen witnesses were there?
three