Detectives arrested the boyfriend of the toddler's mother. Daniel Vega, 25, was taken into custody in West Covina around 11:20 p.m. Thursday. He was wanted for a parole violation and was being held without bail.
The toddler, identified as Gabriel Dominguez, was pronounced dead Thursday afternoon at his home on the 26000 block of S. Western Ave. at the at the Harbor Hills Housing Project. Investigators said the boy had obvious signs of trauma, including bruising to his body.
Neighbors said the suspect was babysitting the toddler while the mother was away from the apartment.
"It's just sad, I don't even know why she would let that man in her house," said neighbor Charmaine Lemelle.
Others said they never heard any sort of screams coming from the home.
"He was a sweet little boy, seemed like he was happy. [I] never saw any signs of any abuse or anything like that," said neighbor Anthony Brown.
Authorities said the mother was cooperating with investigators and was not considered a suspect in the case.
There were two other children living in the residence that were taken into protective custody and are currently with the Department of Children and Family Services, according to L.A. County Sheriff's Lt. John Hocking.
Authorities have not released a motive for the child's murder.