Authorities in the California city where two women and three young girls were found slain over the weekend said Monday that investigators are also looking into last year's death of the 2-year-old son of one of the victims.
The toddler died in Children's Hospital in Modesto in October, according to the death certificate for Christopher Ripley.
The Stanislaus County coroner said the cause of death is still under investigation. The coroner and the Modesto Police are investigating the boy's death, Sheriff's Sgt. Ed Ridenour said. Ripley was the son of Amanda Crews, 38.
Crews was found dead in her Modesto home along with her 6-year-old daughter, 6-month-old daughter and two other females who authorities have declined to identify. Modesto Police spokeswoman Heather Graves said the all the victims are related.
Police arrested Martin Martinez, the former boyfriend of the boy's mother, on suspicion of homicide Sunday in San Jose. Martinez is the father of Crews' 6-month-old daughter.
Martinez was transported back to the Stanislaus County jail at 10 p.m. Wednesday night, according to Modesto Police Department.
Crews was a doctor and worked for the Stanislaus County Health Service Agency, according the California Medical Board. The agency didn't return several phone calls.
Modesto Police have remained tight-lipped about the five homicides, declining Monday to release the cause of death, discuss possible motives or say when the victims died. Their bodies were found at about 3:30 p.m. Saturday after police received a call asking for a "security check'' of the home.
Graves said counselors and chaplains are available for the officers who first entered the home and made the grisly discovery. A group of law enforcement officials could be seen huddled together and praying in front of the house shortly after the discovery of the bodies.
Investigators had named Martinez as a "person of interest'' in the case Saturday and said he was last seen driving a red Lincoln Navigator.
Officers found the vehicle abandoned in the southeastern part of San Jose, San Jose police spokesman Albert Morales said. Martinez switched vehicles and drove off with a relative, Morales said.
Police found the second vehicle in a parking lot after midnight and waited for Martinez to return, Morales said. He was arrested without incident.
The house is in an upscale subdivision lined with four- and five-bedroom homes that were built less than 10 years ago.