SAN LUIS OBISPO, Calif. (KABC) -- Four police officers have been arrested on suspicion of physically abusing 13 children attending a police-run boot camp in San Luis Obispo.Huntington Park Police Department's Marissa Larios, 36, and Patrick Nijland, 47, and South Gate Police Department's Carlos Gomez-Marquez, 31, and Edgar Gomez, 35, were arrested this week. All four posted $20,000 bond.From May 17 to 24, the one-week Leadership Empowerment and Discipline Boot Camp Program brought at-risk youth to Camp San Luis Obisbo, a National Guard military base.Promotional materials say the program, which is sponsored by Huntington Park and South Gate police departments, is designed for children experiencing behavior or disciplinary problems.The San Luis Obispo County Sheriff's Office began its investigation on May 28 after receiving reports of abuse from the Los Angeles County Department of Children and Family Services.In early June, an attorney for some of the children involved said some had been beaten bloody and one suffered broke fingers."They never told me that they were going to beat them or they were going to put them in a dark room or they were going to fracture him or break his arm," said Veronica Bernal, the mother of one of the children."When they didn't do their exercises the way they were supposed to, they were stomped in the back. Their fingers were stepped on," said Araceli Pulido, who had two daughters at the camp.Of the 37 camp participants, 13 male and female victims, ranging from 12 to 17, claimed they had been assaulted by officers at the camp, sheriff's officials said.Sheriff's detectives arrested the four officers involved on Tuesday and Wednesday.The South Gate Police Department issued a statement on its website saying, "We support the San Luis Obispo Sheriff's and the District Attorney's Office regarding the need for transparency in this matter and we will continue to cooperate with them as is necessary and appropriate."Gomez and Gomez-Marquez were arrested on suspicion of willful cruelty to a child, criminal threats, criminal conspiracy, criminal battery and abuse under color of authority.Larios was arrested on suspicion of willful cruelty to a child, criminal conspiracy, criminal battery and abuse under color of authority.Nijland was arrested on suspicion of willful cruelty to a child, criminal battery and abuse under color of authority.