PHOENIX (AP) — A man accused of killing nine people in metro Phoenix grew up in a household plagued by domestic violence, left home at 16 to live with his girlfriend and was in prison three years later for manslaughter after participating in a robbery at a strip club where an accomplice was fatally shot, court records show.

The documents paint a bleak picture of Cleophus Emmanuel Cooksey Jr., characterizing him as a repeat criminal offender who was physically abused as a child and spent 13 years in prison for two robberies. His prison stint ended four months before the serial killings began in late November.

Police say the 35-year-old Cooksey fatally shot the nine people, including his mother and stepfather, in less than three weeks. He was initially charged with killing those relatives then linked to the other seven deadly attacks through ballistics and other evidence.

Police, however, have not released any possible motive for the fatal shootings.

Police say one victim was killed while selling marijuana to Cooksey. Another was a woman whose partially nude body was found in an alley after she was sexually assaulted. The brother of Cooksey's ex-girlfriend was fatally shot as he was sleeping on a chaise lounge.

The court records from Cooksey's earlier criminal cases say his father physically abused him, though the elder Cooksey denied the allegation. The boy was taken to a hospital after one instance of abuse, according to the documents.

Cooksey's mother said her son was suffering from depression when he was 9. He later dropped out of high school, moved in with his girlfriend and used marijuana daily and PCP occasionally, the records show.

Cooksey's father, 57-year-old Cleophus Emanuel Cooksey Sr., is now in federal prison serving a five-year sentence after acknowledging that he started fires in 2015 at a post office in Tucson.

Experts say the recent shooting deaths in the Phoenix area technically fit the definition of serial killings because of the large number of victims.

But they say the attacks go against stereotypes about serial killings, which are typically done patiently and methodically over months or even years.

"This is not your intelligent serial murderer who operates over years," Mike Rustigan, a professor emeritus of criminal justice at San Jose State University who has studied serial killers, said about the attacks. "This guy isn't the great white shark of the criminal underworld."

Jack Levin, a criminologist at Northeastern University in Boston who has written several books about serial killings, said such crimes are often motivated by the killer's need to avenge a catastrophic loss in their lives such as losing a job, falling deeply into debt or breaking up with a romantic partner.

Levin pointed out that Cooksey is accused of fatally shooting the brother of his girlfriend, who had broken up with him a day before the killing. However, it was the fifth killing in the series.

"This may very well have been a message of vengeance that he directed toward his ex-girlfriend to kill what she loves — mainly her brother," Levin said.

Police say Cooksey was wearing a stolen necklace during his arrest that belonged to one of the victims, and a handgun stolen from another victim was found at his mother's apartment after she and her husband were killed.

Cooksey has been charged with murder in the deaths of his mother and stepfather. Authorities re-booked him Thursday in the seven other killings, though he hasn't yet been formally charged in those deaths.

Gary Beren, an attorney who represents Cooksey, didn't immediately return a phone call and email seeking comment on Friday. Cooksey hasn't yet entered a plea.

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