Los Angeles (CNN) -- Prosecutors will seek the death penalty for a 24-year-old former Marine charged with a "serial thrill-kill spree" that killed four homeless men and a mother and her son, the Orange County, California, district attorney said Monday.
Itzcoatl Ocampo is scheduled to be tried in September on six counts of murder with special circumstances for the stabbings.
Ocampo served in the Marines from July 2006 until July 2010 and was deployed to Iraq for six months in 2008, according to Marine service records. He completed his service, with the rank of corporal, with the 1st Marine Logistics Group at Camp Pendleton, south of Orange County.
The first killings happened on October 25, 2011, when Raquel Estrada, 53, and her 34-year-old son Juan Herrera were left dead on the floor of their Yorba Linda home, Orange County District Attorney Tony Rackauckas said. Estrada was stabbed more than 30 times and Herrera was stabbed more than 60 times.
DNA evidence links Ocampo to the crime scene, which is a mile from his home, Rackauckas said. The defendant was a childhood friend with a man who was the son and brother of the victms, he said.
"The nature of this crime was similar to the murders of four homeless men, in that all six victims were stabbed in a like manner and suffered a substantial number of stab wounds to the upper body," the prosecutor said.
The four homeless men were killed over a 24 day period starting on December 20, 2011, when 53-year-old James McGillivray was stabbed "more than 40 times in the head, neck, and upper torso," the prosecutor said.
The killing, behind a commercial complex in Placentia, California, was recorded by a video surveillance camera that the property management company installed just days earlier, the prosecutor said.
Lloyd "Jimmy" Middaugh was killed a week later under a highway overpass in Anaheim, where he was "taking shelter," the prosecutor said. Middaugh, 42, was stabbed to times in the head and torso, he said.
Paulus "Dutch" Smit, 57, died when he was stabbed 60 times while in the area of the Yorba Linda Public Library on December 30, 2011, he said.
A multi-agency Homeless Homicide Investigative Task Force was created the next day "based on the similarities between the three murders and suspicion by law enforcement that one person was responsible for all three attacks," the prosecutor said.
Ocampo was arrested in a mobile home park in Anaheim soon after witnesses saw him flee the scene of the stabbing death of 64-year-old John Berry on January 13, 2012, Rackauckas said. "At the time of his arrest, Ocampo is accused of having blood on his hands and face," he said.