The third suspect in the murder investigation of a 15-year-old Mountain View girl says she didn't know the full scope of what the other suspects intended when she drove them to the scene of the crime.

Jamal Townsend, 24, and Lammar Burney, 28, were charged earlier this week in the shooting death of 15-year-old Precious Alex. Police say they fired into her bedroom in a basement apartment as she slept early Tuesday morning, killing her and injuring an unnamed juvenile male. A third suspect, Karlie West, 21, was charged Thursday night for her involvement in the murder.

According to charging documents, West told police during her initial interview that Townsend -- who she knew only as "Millz"—was at West’s apartment with Burney, and seemed agitated by an incident between himself and the fiancé of the victim's mother two weeks before.

Later that night, the three ended up in West’s car, and “Millz” said he wanted to seek some form of revenge against the fiancée. West told police that she could hear what sounded like a gun being handled by the two men in the vehicle, but wasn't sure. She noted Townsend had brought a handgun into her apartment earlier that day, but believed they intended only to intimidate or fight the fiancée, not shoot him. 

Police say she was given the address of the apartment, and told to wait in the vehicle. The two men left, and fired shots through the bedroom window, came back to the car and told her to drive. 

Police in the Mountain View area noticed West's silver Jeep Cherokee fleeing North Flower St. just before they received a radio call for a shooting victim located on North Flower St. As some officers responded to the call, Officer B. Wilson followed the vehicle and conducted a traffic stop, during which a search revealed a Smith & Wesson .40 caliber semi-automatic weapon under the driver’s seat. A matching magazine was found empty, and the gun was noted to be locked open in the empty position.

The two men in the vehicle were arrested at the scene, for an outstanding warrant and another charge unrelated to the shooting. Police impounded the vehicle and took West into custody for questioning. 

Assistant District Attorney Paul Miovas explained during a phone interview that West was being charged with second degree murder and third degree assault for her participation in the murder. Miovas says the severity of the charges stems from her awareness of Townsend and Burney’s intent to harm someone, and then her continued help even after knowing shots had been fired by the two men.

He says her actions in driving them to and from the crime scene make her a knowing accomplice in the eyes of the law.

Burney was arraigned earlier in the week, with bail set at $1 million. Townsend was arraigned on Thursday and remanded under a bail of $1.5 million. West was arraigned Friday at 2:30 p.m.

KTUU's Chris Klint and Matthew Smith contributed to this story.