Refugio Ocampo said in an interview with the Associated Press that his son, 23-year-old Itzcoatl Ocampo, returned from the service a very different and disillusioned man. He also mentioned his son was having difficulty re-adjusting to civilian life.
Refugio also said that his son approached him Jan. 11 with a photo of the first murder victim as a warning about the killings. Refugio said his son seemed worried.
"He was very worried about me. I told him, 'Don't worry. I'm a survivor. Nothing will happen to me. I will find something. Count on it,'' he said.
Itzcoatl Ocampo is a 2006 graduate of Esperanza High School in Yorba Linda and a former Marine who served in Afghanistan.
Ocampo was arrested Friday night after another homeless man was stabbed to death near a Carl's Jr. restaurant in Anaheim. Bystanders and witnesses at the crime scene chased Ocampo, who was later captured by police.
Orange County authorities said they're confident they have the right suspect in the serial murders, but the motive still remains a mystery.
The latest victim was identified as 65-year-old John Berry. A candlelight vigil was held Saturday night in Berry's honor. Friends say Berry was nervous and out-of-character days before his murder. He told them he was being followed by someone.
"He said, 'I think I came in contact with the serial killer last night.' About the time he was telling me the story, there was a gentleman from the department of water that was driving into the river trail and I flagged him down and I said, 'You need to call the police,'" said Berry's friend, Jim Burke.
Eyewitness News has learned that the Anaheim Police Department received a report indicating a homeless person was being followed, but authorities aren't confirming if that report came from Berry.
Friend Chris Juarez and his aunt told Berry to stay with them in a spare bedroom, but Berry refused and said, "I'm not scared of death."
"It took another victim, John, but it's over. Now, the homeless people can rest at night now," said Brad Olsen, Berry's brother-in-law.
Berry was the fourth victim in the string of murders since mid-December.
James McGillivray, 53, was found fatally stabbed Dec. 21 outside a strip mall in Placentia. A week later, 42-year-old transient Lloyd Middaugh was found stabbed to death near the Santa Ana River Trail in Anaheim. Two days after his murder, the bloody body of 57-year-old homeless man Paulus Smit was found next to the Yorba Linda Public Library.
"I don't know why the assailant did what he did. He didn't even know John. He didn't know the other people," said Anaheim resident Robert Reid. "I'm having a hard time understanding his mindset."
A steady stream of people continued Sunday to visit the Carl's Jr. where Berry was killed, with many adding more candles and flowers to the growing make-shift memorial.
"He was really smart. He was always happy. Pretty much, he didn't think of himself as homeless. He had a home, and it was in the community. It was like pretty much in the people that he knew," said Anaheim resident Bryce Sage.
Ocampo was booked at Anaheim City Jail without bail. He has since been transported to Orange County Jail in Santa Ana. He is expected to face four counts of murder.
Orange County District Attorney Tony Rackauckas's office told Eyewitness News a tentative news conference was scheduled for Tuesday to release more details about the investigation. The DA's office said it has not determined whether the death penalty will be sought in this case.
The Associated Press contributed to this report.