Investigators are searching for a serial arsonist who they believe torched nine vehicles within a 24-hour period in the Upper Marlboro area.

Four fires were set early Wednesday and another five fires were spotted early Thursday in residential areas of Upper Marlboro, Kettering and Lanham-Seabrook, said Mark Brady, a spokesman for the Prince George’s County fire department. No one was injured in the incidents.

“Whenever you have that number of fires are occurring, we’re fortunate that none have been close to a house, and firefighters have been able to extinguish them without any other issues,” Brady said.

Investigators think the fires are linked, but they declined to discuss specifics about how they were set.

All the vehicles were parked on the street in front of their owners’ homes, Brady said. Some cars were significantly damaged and others were totaled, he said.

Authorities ask that residents lock their vehicles and report any suspicious behavior.

“Needless to say, after having two consecutive mornings of this, both fire and police will increase patrols throughout that area for the foreseeable future,” Brady said.

Officials ask anyone with information to call 301-772-7766.