CA police say sure they've found homeless killer (AP) - For a month, a killer who authorities believed was targeting homeless men had investigators scrambling to track down a suspect as three stabbing deaths put fear into the homeless population in the Orange County suburbs. The killing of yet another homeless man over the weekend led to the arrest of a suspect in that and earlier deaths. "We are extremely confident that we have the man that is responsible for the murders of all four homeless men in Orange County," Anaheim Police Chief John Welter said at a Saturday news conference. The man in custody, Itzcoatl Ocampo, 23, of Yorba Linda, was arrested Friday night after a man was found stabbed to death in the parking lot of a Carl's Jr. restaurant, Welter said. Witnesses and bystanders at the crime scene chased Ocampo, and he was captured by a police officer who was part of a perimeter set up in response to dozens of 911 calls and other reports. On Saturday the scene was covered with flowers and signs left in tribute the latest victim. As the stabbings continued last month, a task force that included the FBI and four local police agencies formed to find the killer. Authorities would give no further information on Ocampo, the evidence against him or any suspected motive. Ocampo is being held without bail at the Anaheim jail. A phone number listed in Ocampo's name rang without an answer, and no one answered the door at the address where he had been living. Family and friends said Ocampo served in the Marines in Iraq, and was mentally troubled when he returned in the summer of 2010, telling those close to him that in the year since he'd been seeing and hearing things. "When he came back from Iraq, he was sick," Ocampo's uncle, Ifrain Gonzalez, told the Los Angeles Times. Neither the Times nor The Associated Press was able to reach Marine officials to confirm details. Investigators searched Ocampo's home in Yorba Linda on Saturday morning and left with shoes, clothing and a computer, according the Orange County Register. Ocampo graduated from Yorba Linda's Esperanza High School in 2006, and had been living back in his hometown with two younger siblings, landlord Jim Tice told the Register. Word of the arrest was greeted with cautious optimism among the Orange County homeless and their advocates. "It was the topic of a lot of conversation tonight, and everybody was really excited, just really happy and relieved," said Larry Haynes, executive director of the Mercy House shelter in Santa Ana. But until there is a conviction and we know for absolute certainty, we're hoping that people will try to stay safe. Friday night's victim, 65-year-old John Berry, was interviewed by a reporter from the Los Angeles Times looking into the killings earlier this month. Berry, living under a tarp along a riverbed, said then that he wasn't scared enough to go to a shelter. "I just like to stay outdoors," he said. A guy can get killed crossing the street. I've been as careful as I can, watching and everything. But in the days before his death he was uncharacteristically nervous, according to Marilyn Holland, an Anaheim woman who had befriended him and often brought him cookies. "He told me he thought he was being followed," Holland told The Associated Press. Holland was having dinner at a nearby restaurant Friday night when she saw dozens of police cars descending on the Carl's Jr. parking lot, and heard they had found a homeless man dead near the trash bin. The other men killed were all found stabbed to death like Berry. Associated Press Writer Andrew Dalton in Los Angeles contributed to this report.