LOS ANGELES (CBS) — The murder of a Los Angeles gang member killed after being shot on two separate occasions has left homicide investigators stumped.

KNX 1070′s Brian Ping reports they’re having trouble determining which shooting ultimately killed him.

When the unidentified 20-year-old man died in a hospital Tuesday, authorities first believed it was from wounds he suffered in a shooting last year near Western and 120th Street in unincorporated Athens.

But an investigation by the Los Angeles County Sheriff’s Office revealed that the man had been released from the hospital and had been injured in a much more recent shooting in Los Angeles.

Now they’re trying to find out which one was the fatal bullet.

If it was from the second shooting, the Sheriff will turn the investigation over to the LAPD.