Authorities took Luis Aurelio Morales, 25, into custody and booked him on suspicion of murdering Kayla Huerta.
Huerta, a 17-year-old mother from the Wilmington neighborhood of L.A., was found shot to death inside a car that had crashed in the 700 block of Sepulveda Street on June 18.
RELATED: Teen found shot, killed in car after San Pedro crash
Police allege Huerta was with a group of people when Morales became upset and shot her.
His bail has been set at $3 million.
A GoFundMe page has been set up to help Huerta's family.