Two men face murder and conspiracy charges in connection with Oliveras' death: Trent Larelle Jackson, 18, of Coatesville, and Efrain Molina, 28, of West Chester. Police said they are seeking a third suspect.
Police have identified Anderson as the girlfriend of Jackson, who was awaiting trial for alleged marijuana possession, and Deveaux as a friend of Oliveras.
"These were not random acts of violence," said West Chester Police Chief Scott L. Bohn. "We believe the victims were the intended targets."
A few minutes before the shooting of Anderson, according to the criminal complaint, Deveaux had threatened to shoot David Cruz in the alley of the 200 block of East Market Street, repeatedly saying: "I know you were involved in the other night."
Cruz told police he saw the gun and took off, escaping into a nearby house, the complaint said.
Deveaux may have unwittingly played a role in Oliveras' drug case, according to court records. In responding to a report that Deveaux had been the victim of a drive-by shooting in June 2006, police began an investigation that led to the Oliveras residence and eventually resulted in the charges against him.
Bohn called Thursday night's shooting in a residential area during daylight "a brazen act," but added that the response time to the second incident "was almost instantaneous." He said detectives were in the area investigating the homicide when they heard shots.
Bohn said police will be targeting the area, and anyone with information is asked to call 610-696-2700.
Contact staff writer Kathleen Brady Shea at 610-701-7625 or kbrady@phillynews.com.