The FBI is investigating two bombings that targeted university scientists, the latest in a rash of attacks against biomedical researchers who experiment on animals, authorities say.

Both scientists work at the University of California, Santa Cruz. One of them and his family were forced to escape from a second-story window early Saturday when a firebomb was lit on the home's porch, Santa Cruz police said. An adult was treated at a hospital and released.

Police Capt. Steve Clark called the bombing "an attempted homicide."

Also that morning, a firebomb destroyed a car belonging to another researcher. Clark said authorities were treating the attacks as "domestic terrorism."

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

"Animal abusers everywhere beware," the pamphlets read. "We know where you live."

Molecular biologist David Feldheim, whose front door was charred, was listed in the pamphlet. According to his Web site, Feldheim's lab uses mice to study the development of brain functions involved in eyesight.

Authorities would not identify the researcher whose car was destroyed but said that person was not named in the pamphlet.

Police said they have no suspects in Saturday's attacks, the first since February, when animal rights activists showed up at the house of a UC Santa Cruz breast cancer researcher during her young daughter's birthday party.

The masked protesters pounded on the front door, and one threw a punch at the researcher's husband as he tried to chase them away, according to police. The FBI is still investigating.

In recent years, three UCLA researchers who use non-human primates have been targeted with firebombs. Animal rights groups claimed responsibility for all three attacks.

More recently, masked protesters targeting UC Berkeley have scrawled graffiti and broken windows at scientists' homes.

FBI investigators said the attacks at different universities are probably not centrally coordinated. They do share similar tactics, however, including posting researchers' personal information online and in print, investigators said.

"These are odious assaults on individuals and on the principles of free inquiry by which we live," UC Santa Cruz Chancellor George Blumenthal said in a statement Saturday.

Police said they plan to boost security for UC Santa Cruz researchers whose names appeared in the pamphlets discovered last week.