A gasoline-filled device in a car bomb fails to go off. Authorities investigating another bombing incident find that after a first bomb exploded, a second bomb was timed to go off when first responders arrived. A recent event in the United Kingdom? Yes, but also in California.

Last week, the Los Angeles Times reported that a bomb was discovered outside the Westside home of Dr. Arthur Rosenbaum, the chief of pediatric ophthalmology at UCLA's Jules Stein Eye Institute. The car bomb failed to explode, despite apparent attempts to detonate it.

In 2003, two bombs exploded at biotech firm Chiron's Emeryville office. Agents believed the second bomb was timed to go off when first responders arrived.

The terrorists behind the American firebombs were not Islamic fanatics, but animal-rights jihadists bent on harming and intimidating scientists who conduct medical research on animals. They also have targeted employees of businesses that might work with researchers, as well as harassed the spouses and young children of researchers.

Americans for Medical Progress President Jacquie Calnan warned that the latest incident "marks a disturbing escalation in the tactics of intimidation and harassment."

Last year, animal-rights activists went after another UCLA researcher by placing a firebomb at her doorstep -- except that they put the bomb at the wrong home. Fortunately, that bomb, too, failed to ignite.

While the bombs did not go off, FBI Special Agent Kenneth E. Smith observed, "the devices could have detonated, resulting in significant damage."

So far, animal rights activists have not killed anyone in the United States, but that does not mean Americans should not fear these extremists. In October 2005, Dr. Jerry Vlasak, a Southern California trauma surgeon who is a leader of the North American Animal Liberation Front, testified before the U.S. Senate and defended killing researchers in order to stop research using animals.

"I don't think you'd have to kill -- assassinate -- too many," Vlasak opined. "I think for 5 lives, 10 lives, 15 human lives, we could save a million, 2 million or 10 million nonhuman lives.''

And the threats of violence and intimidation work. Last year, UCLA researcher Dario Ringach sent an e-mail to Vlasak in which he proclaimed, "You win" -- he would stop research with animals. Vlasak sent out a triumphant press release. Continued...