It was the fourth dental office to be torched along Sierra Avenue since the beginning of April. Police and fire investigators say there are strong similarities that connect the fires.
"The starts were similar, I can say that in that a heavy object being thrown through glass and then gasoline introduced into the building," said Mike Horton, deputy fire marshal, San Bernardino County Fire Dept. "Those are the sorts of sets that we're coming across."
The first three fires happened around Easter. One office was damaged on April 7. It has now reopened. A few blocks away, two dental offices were severely damaged by fire around the same time.
One office is closed for repairs. The other is open but no one at the office wanted to talk on camera. Off-camera, employees said they're concerned for their own safety and the safety of their patients. One employee says it's making some of her co-workers nervous. They wonder, she says, if their office will be hit again.
According to the San Bernardino County Fire Department, a multi-agency task force that includes Inland Empire fire and police investigators is now helping out with the investigation.
Investigators say they don't have a description of who they're looking for. They say they still have to determine if they're dealing with one or more suspects.
"We don't have any suspect information at this time, but as that develops, we'll make that known," said Horton.
No one was injured in any of the four fires.
If you have information related to the fires, call the Arson Hotline at (800) 47-ARSON.