Four children told police they were sexually abused by their own parents, as well as their grandfather and uncle. It allegedly happened at a home on Stetson Avenue near Hemet.
The mother, Monica Silva, the uncle, Ronald Hurley Jr., and the grandfather, Ronald Hurley Sr., were arrested and charged with sexual assault, child endangerment and penetration by force. The father of the children, who is currently serving time in state prison, will also be booked.
The uncle is an amateur boxer and is known in the area as the "San Jacinto Kid." Law enforcement said the grandfather's background includes an arrest for statutory rape 12 years ago.
"We're still completely shocked," said Riverside County Sheriff's Cpl. Courtney Donowho. "This is just a terrible, dreadful incident, and this shouldn't happen to any child growing up, much less four children in one home."
Detectives said the sheriff's department opened the investigation after one of the kids reported the assault. It culminated with three arrests at the place where the family had recently moved to on State Street in San Jacinto.
"Investigators are trying their best to protect the children and their privacy in this incident," said Donowho.
The children have been taken in Child Protective Services. Meanwhile, the suspects remain in police custody.