"I'm outraged that my son is dead," said mother Mary Ann Nevil.
Nevil said she has two other sons who are marines, serving tours of duty in Iraq.
"I have two sons fighting for the freedom of this country, while their brother was murdered right here," she said.
Sheriff's deputies say they found Jonathan collapsed next to his bicycle on Pioneer Boulevard under the 91 Freeway overpass.
His mother said she saw her son before she went to bed Tuesday night.
"He was at home making hamburgers," Nevil said, adding that for some reason he went out.
She got a knock on her door at 4 a.m.
"I don't know what he was doing out here, I don't know where he was coming from, I don't know where he went. I just know that somebody stole my son from me," said Nevil. "He was 17-years-old and I'll never see him again."
Jonathan's friends said they think the shooting was an act of gang violence.
"Who else would go around shooting a kid on a bike," said Jonathan's friend Gershim Young.
"I got a hatred in my heart right now that somebody had the intention just to kill a 17-year-old boy for no purpose ... no reason at all," said Henry Hernandez, Jonathan's friend. "And I just don't know what's going on in people's heads nowadays."
Jonathan's friends say they even worry about their own safety.
"Being out here now ... you never know. Standing out here on the corner like this ... you don't know," said Bryan Medeiros, Jonathan's friend.
"It makes you think, if you're walking down the same street, it might happen to you. It just makes you wonder," said another one of Jonathan's friend, Enrique Saavedra.
Police have no motive for the shooting and no suspect description.
Anyone with information is urged to call Los Angeles County Homicide detectives at (323) 890-5500.
Eyewitness News Reporters Leo Stallworth and Leslie Miller contributed to this report.