FILE PHOTO: Cleophus Cooksey, Jr., a convicted felon arrested for shooting and killing his mother and stepfather in their residence in December is shown in this undated booking photo in Phoenix, Arizona, U.S., provided January 18, 2018. Phoenix Police Department/Handout via REUTERS/File Photo

PHOENIX (Reuters) - A convicted Arizona felon has been formally charged with eight counts of first-degree murder over a series of fatal shootings on Phoenix-area streets late last year, court documents showed on Monday. Cleophus Cooksey Jr., 35, was also charged with armed robbery, kidnapping, sexual assault and burglary during the three-week crime spree, according to a state grand jury indictment handed down on Thursday and made public on Monday.

Police have said Cooksey committed nine murders, beginning in November when two men were found fatally shot in a parked car. The rampage ended with his mother, Rene Cooksey, and stepfather, Edward Nunn, shot dead in their living room.

It was not clear whether he was only charged in eight of those nine killings.

Cooksey has been in jail since Dec. 17, when the blood-stained suspect was arrested by police over the death of his parents.A police spokesman has said there was ballistic evidence linking the crimes in addition to other evidence and witnesses.Cooksey’s attorney, Gary Beren, could not be reached for comment on Monday.The murders rank among the highest attributed to a single person in state history and the second such killing spree in Phoenix in a year. In May, police linked 12 shootings and nine deaths to a former city bus driver who has pleaded not guilty.Police said there was no known motive for the killing spree that claimed seven men and two women, with the victims ranging in age from 21 to 56 years old. Apart from his mother and stepfather, police said Cooksey had no personal connection to the other victims for which he was indicted. Five days after the two men were found shot in their car, officers found an adult male dead near a roadway and learned that the man’s handgun had been stolen.

Two more killings followed in the next several days and, on Dec. 16, officers discovered the dead body of a woman who had been sexually assaulted in an alleyway.Cooksey is accused of killing his mother and stepfather the next day.Cooksey has a long criminal history that includes manslaughter and armed robbery, prison records show.