JACKSONVILLE, Fla. >> A 12-year-old Florida boy was under arrest Thursday and accused of fatally shooting a homeless man in the head during a "horrific event," police said.

The boy is suspected in the killing of 54-year old Thomas Trent after being identified in a surveillance video by investigators, said Jacksonville Sheriff’s Office Assistant Chief Chris Butler.

The State Attorney’s Office has not yet filed charges in the case, and declined further comment on the investigation.

"It’s a horrific event," said Butler at a news conference. "Horrific for the victim … but also you’re talking about a 12-year-old child."

Trent’s body was found June 28 at a vacant business building.

Butler says surveillance video from a nearby dental care office and a tattoo business showed two young men walking near the site of Trent’s slaying at 2:25 a.m.

Six minutes later, the cameras also captured the two running behind a strip-mall near the site where Trent’s body was found "with their shorts on their heads," a sheriff’s arrest report states.

The report also said that the other boy in the video — identified as a 16-year-old who was being held in jail on an unrelated charge — was found and identified the 12-year-old as the one who shot Trent.

The weapon used in the shooting has not been recovered, Butler said. He said the 16-year-old is not a suspect in Trent’s slaying but didn’t elaborate.

"The suspect gave admissions, and he identified himself in the video and being present and involved in the murder," Butler said of the 12-year-old.

Trent’s sister told the Florida Times-Union that her brother was kind and intelligent, and had just been released from the hospital when he was killed. He’d suffered from health problems related to alcoholism, she told the paper.