Four people were found dead Wednesday in a San Francisco home in what police are calling a case of “suspicious deaths.”

Officers discovered the bodies during a welfare check at a million-dollar residence on Monterey Boulevard in an upscale neighborhood.

The victims, believed to be family members, were pronounced dead at the scene, and investigators are exploring the possibility of a murder-suicide.

Neighbors described the family as quiet and friendly, noting they had lived in the area for about a year, Fox News has reported.

The San Francisco Police Department’s homicide unit and the Medical Examiner’s Office are investigating, with officials yet to release the victims’ identities or causes of death.