The L.A. City Council is offering a $50,000 reward in the shooting death of Carlos Segovia-Lopez. 

The 19-year-old Marine, who was stationed at Camp Pendleton, was on weekend leave last Friday in South L.A. He had just dropped off his girlfriend when he was shot while driving down West 31st Street.

LAPD Captain Peter Whittingham tells our media partner NBC4 Segovia-Lopez  may have witnessed a crime or other suspicious activity.

"We have not yet located any evidence, witness, video that would lead us in a direction as to who is responsible for this senseless act," Whittingham said.

Police say he was on the phone when it happened. They have a recording of the call and gunshots can be heard.

Segovia-Lopez was taken off life support and died Monday. On Tuesday, friends and family held a vigil for him at the site of the shooting.

He was well known in his South L.A. community for his volunteer work. He led a youth group called Teen Project that pushes high school students to finish school. He also worked at LA on Cloud 9, a group that provides services to homeless people and animals, according to the LA Times.

Cynthia Lopez, his 13-year-old sister, told NBC 4 she plans to dedicate her life to living out some of her brother's dreams: "Now what I want to do is finish his dream to become a USC graduate and become maybe part of the Navy."

His fellow Marines at Camp Pendleton also celebrated his life with a memorial video.