A man was arrested on charges he sexually assaulted and murdered his girlfriend’s 3-year-old son, the Broward Sheriff’s Office said Thursday.

Victor James Vance, 40, of the 1800 block of Southwest 41st Avenue west of Fort Lauderdale, was charged with murder and sexual battery in the death of Thomas Kidwell, the son of his live-in girlfriend, Dawn Kidwell, 22, from a previous marriage.

Vance admitted beating the child, explaining he became angered after the boy soiled his pants, according to an arrest affidavit.

The yard outside the apartment Vance and Kidwell shared was still roped off with yellow crime scene tape on Thursday. A tiny red three-wheel cycle with tassels on the handgrips sat in the middle of the yard.

Detectives say Vance, who is unemployed, has an extensive arrest record in Nevada for crimes such as burglary and arson. He told detectives he has served about 2 1/2 years in prison. He is being held in the Broward County Jail without bail.

Police were sent to the apartment about 12:30 p.m. Wednesday after Vance called 911 to report the child was not breathing. Paramedics tried to treat the child, then rushed him to Plantation General Hospital, where he was pronounced dead.

Deputies said Vance gave several different stories explaining how the child was found unconscious in the yard of the apartment building.

He said he found the child unconcious in the yard, then blamed his girlfriend for the beatings, then said he beat the boy after he soiled his pants, Broward sheriff’s homicide Sgt. Richard Scheff said. Vance refused to make a statement regarding the sexual assault of the boy, police said.

Broward County Medical Examiner Ronald Wright determined Thomas died from blunt trauma to the chest and abdomen. His investigation also revealed evidence of sexual battery.

Dawn Kidwell, a hair stylist, was at work when Vance made the emergency call. She later told detectives she had suspected that Vance had been abusing her son because she noticed the boy often would have a series of injuries after being left alone with Vance, the affidavit states.

“There was always another excuse as to why the kid had another injury,” Scheff said. “She apparently kept believing him.”

Kidwell said the day her son died, Vance had called her to say the boy had bruises and a cut lip.

A witness told deputies that about a half hour before police arrived at the apartment, he had seen Vance dragging the apparently unconscious child down the street.