San Francisco ? The parolee who killed three Oakland police officers and left a fourth brain-dead over the weekend had been tentatively linked by DNA evidence to a rape the day before the shootings, authorities said.

Oakland police spokesman Jeff Thomason confirmed a report on the San Francisco Chronicle’s Web site on Monday night that DNA from an unsolved rape in Oakland in February was a probable match to that of 26-year-old Lovelle Mixon.

Investigators got that information Friday, the day before Mixon opened fire on the officers following a routine traffic stop. Mixon is the primary suspect in the rape and is being investigated to see if there are any connections to other rapes, Thomason said.

Thomason said further tests would need to be done on the DNA in question to make sure it is a solid match.

Earlier Monday, state Attorney General Jerry Brown said he will examine how 26-year-old Mixon was monitored following his release from prison in November on a conviction for assault with a deadly weapon. Mixon also was a suspect in a murder last year but was never charged, according to state prison officials.

Problems involving parolees from California’s overcrowded prison system have long beset state officials who must monitor them, local officials who try to keep streets safe and federal authorities who enforce firearms and other laws.