San Francisco ? The FBI is investigating two firebombings targeting scientists at the University of California, Santa Cruz, as the latest in a rash of attacks against biomedical researchers who experiment on animals, authorities said.

One scientist and his family, including two small children, were forced to flee from a second-story window Saturday after a firebomb was lit on their front porch, filling the off-campus house with smoke, Santa Cruz police said. An adult was treated for minor injuries at a hospital and released.

Police were investigating the attack as attempted murder, said Santa Cruz police Capt. Steve Clark.

“That device had a real potential to put that family in jeopardy,” Clark said. He described the bomb as a “Molotov cocktail on steroids.”

A sprinkler system and a neighbor with a garden hose helped keep the fire from spreading before firefighters arrived to extinguish it, Clark said.

Also Saturday morning, a firebomb destroyed a car belonging to another researcher parked at faculty housing on campus. Investigators said they were treating the attacks as “domestic terrorism.”

The attacks came four days after police obtained threatening animal rights pamphlets left at a Santa Cruz coffeehouse containing the names and home addresses of UC Santa Cruz scientists.