Lovelle Shawn Mixon (September 11, 1982 – March 21, 2009), a 26-year-old resident of Oakland, was identified as the assailant. He was born in San Francisco.[16] Mixon wielded a 9mm semiautomatic handgun during the MacArthur Boulevard killings, and an SKS rifle during the shootout in the 74th Avenue apartment shootout.[9]

Mixon had an extensive criminal history. Beginning at age 13, he was arrested multiple times for battery, and by age 20 was serving a Corcoran state prison sentence following a felony conviction for assault with a deadly weapon and armed robbery in San Francisco. After he was paroled, Mixon went in and out of prison. When the shootings happened, he was living in East Oakland at his grandmother's house and was wanted on a no-bail arrest warrant for violating his current parole conditions. On March 20, 2009, the day before the shootings.[2] Had Mixon been arrested for his parole violation, he would have faced at most six months in prison.

Mixon had also been the primary suspect in a previous murder case. However, due to lack of evidence he had been charged only with lesser violations, which included possession of drug paraphernalia, forgery, identity theft, attempted grand theft, and receiving stolen property.[17][18]