The dead man was found near a path frequented by those who stay at the camp located along the 4100 block of State Street, according to Santa Barbara County Sheriff's Sgt. Erik Raney, a department spokesman. Authorities were notified of the grisly discovery about 7:30 a.m.
Officials said they believe the victim spent at least one night at the encampment prior to the alleged murder before an argument between the men turned violent, Raney said.
By late morning, forensics experts had descended on the scene, a grassy and tree-dotted area adjacent to the State Street bridge. Noting the man was injured, and taking into account the position of his body, they initially treated the case as a suspicious death, Raney said.
As the investigation unfolded, southbound vehicles zoomed by on the freeway below.
After questioning people who sometimes sleep at the site, detectives determined that the victim and the three men now in custody got into a verbal argument early Thursday, authorities said.
The argument escalated into physical violence and the man was beaten to death, Raney said.
"Several homeless subjects were contacted by detectives at the encampment," Raney said in a statement. "During the course of the investigation, detectives determined that the victim and several of the subjects at the camp were involved in a verbal argument in the early morning hours of (Thursday) June 14th.
"The argument allegedly turned violent, and the victim was severely beaten," Raney said. "The victim was then abandoned."