A suspect or suspects who shot 19-year-old U.S. Marine Lance Corporal Carlos Segovia in the head in South Los Angeles on Friday night were still unknown, as Segovia was declared brain dead Sunday.

Segovia’s mother, Sandra Lopez, is fighting to have her son moved to a hospital that will not pressure her so greatly to take her son off of life support, according to KTLA. The report quoted Lopez as saying, ”A Marine never gives up. I know what my son is going through. So I choose to ask the doctor to take another test and they refuse to do that.”

Segovia was visiting his girlfriend’s home Friday night when a group congregating around his car led the young Marine to approach and ask that they move away from his vehicle, according to police cited by the KTLA news report. Segovia was then shot once in the head around 11:30 p.m. by one or more suspects in a vehicle that pulled along side Segovia’s, according to L.A. Police Department officials cited by ABC7. Segovia was not in uniform at the time of the attack.

The LAPD stated that the incident was not gang-related; however, the suspect or suspects and the car that they were in had not yet been identified, according to ABC7.

Segovia’s family told ABC7 that for years he volunteered with a local group that serves the homeless. The young man’s desire to serve his country led him to join the Marines just six months ago. The teen’s family have asked for just two things: prayers, and that anyone with information would tell police what they know. The KTLA report added reports of family and friends who communicated that he “encouraged at-risk youth to join the Marines.” They said that he was in town over the weekend to do volunteer work.

L.A. on Cloud 9 posted this statement on Facebook as Segovia remained on life support following the shooting:

Prayers are needed for Carlos Segovia. We are heartbroken over this tragedy. He was shot in the head on Friday, September 16 while visiting LA for the weekend, and is on life support. Carlos is a young man who started with LAC9 as a teen who helped develop the Teen Project program, and provided countless support to our homeless community through Street Team Soldiers and our MacArthur Park community picnics. We were fortunate to witness Carlos become a fine young man who graduated from the Marine camp earlier this year and started his service with the US Marines. Please keep Carlos and his family in your thoughts and prayers.

Follow Michelle Moons on Twitter @MichelleDiana