BALCONES HEIGHTS, Texas -- Three men and one woman are now being considered persons of interest in the shooting death of a 27-year-old woman Monday evening.

Sources within the Balcones Heights Police department tell KSAT 12 News they are confident they have the shooter from within the group of four that was taken into custody during a Tuesday afternoon raid.

The group of four have been taken to San Antonio Police headquarters for further questioning.

Rose Ann Martinez, 27, was shot and killed early Monday evening while sitting at a stop light at the intersection of Fredericksburg Road and Crossroads Boulevard. She was a passenger in a green Mercedes being driven by 46-year-old Jose Alberto Lozano, who was also shot and injured, police said.

Just before sunset, a man walked up to the driver's side door and fired several shots inside the vehicle before leaving in a waiting car, police said. Lozano was able to drive to a nearby hotel where police were called.

Investigators are waiting to see if an unlikely witness to the crime might have helpful information.

Balcones Heights Police Chief Bill Stannard said his department is awaiting word from the company that operates the city's red light cameras if the crime was captured digitally.

"They're actually dealing with raw footage, and they have to have the time and date, and then they have to research it to see if it's really there at that intersection, so it takes a little bit of time," Stannard said.

Detectives are also speaking with Lozano, but investigators said he's not being cooperative. Police said the shooting was likely gang-related, but the victims might have just been in the wrong place and the wrong time.