Details remain thin, but police in San Mateo are investigating the deaths of two adults and two children who were found dead inside a home Monday morning in San Mateo's Sugarloaf neighborhood.

The gruesome discovery was made around 9:15 am Monday, as KRON4 reports, when San Mateo police performed a welfare check at the home on the 4100 block of Alameda de las Pulgas.

A male adult, a female adult, and two four-year-old twin boys were found deceased in the home, as ABC 7 reports. Police said there was no sign of forced entry, and this appeared to be an isolated incident.

ABC 7 further reported that investigators appeared focused on a white Tesla parked outside the home with its hazard lights on.

No causes of death have been released.

Update: Police have released very little information as of Tuesday morning, however the county coroner has confirmed that the dead were a family — a husband, wife, and twin boys. No names have been released, and the police have made clear no suspects are being sought, which points to this being a murder-suicide.

Update 2: On Tuesday afternoon, San Mateo police put out a release confirming that the husband and wife were found dead of gunshot wounds inside a bathroom in the home, and a 9 mm pistol was found nearby. The two boys were found in a bedroom, and their cause of death remains under investigation.

This is a developing story.