SANTA CRUZ -- Nationally known animal rights proponents said Wednesday that what they call a weekend "home visit" by protesters to a biomedical researcher's Santa Cruz residence was likely the work of an independent, local group and not a large, established network.

Jerry Vlasak, a Los Angeles-area surgeon connected with the underground Animal Liberation Front, said members of that group are typically more stealth in their confrontations with researchers who use mice and other animals. He said ALF operatives would not drive to a target's home and depart with a visible license plate, as occurred during Sunday's Santa Cruz incident.

"This sounds like an above-ground group doing a demonstration at someone's house," Vlasak said.

He said he did not believe confrontations ALF protesters have instigated with UCLA faculty were related to the Santa Cruz case, which left a UC Santa Cruz researcher's husband with a minor hand injury. Though Vlasak and two other supporters said they have no firsthand knowledge of the loud encounter at the Westside home and didn't know it was planned, they doubted whether it was a "home invasion," as police have dubbed it.

While Vlasak acknowledged that knocking by protesters on the researcher's door could have gotten "out of hand," he said, "It doesn't sound like they hurt anybody or were doing anything illegally." He said it was likely that "police and animal abusers were spinning whatever happened" to demonize demonstrators.

But the researcher, whom the Sentinel is not naming for safety reasons, has said six masked protesters banged on her porch before pulling her front door so aggressively that she was feared her locks wouldn't keep them out. Her husband approached the protesters after she huddled with their children, 2 and 8, and two other children at the house for a birthday party, and told police he was struck on the hand with an unknown object before chasing them off.

The FBI is investigating possible links to "domestic terrorism," and police and university officials have roundly characterized the event as a shocking attack. No arrests have been made and no one has claimed responsibility. UCSC students living in a house raided by police in connection with Sunday's incident have declined to comment.

UCSC's Student Organization Advising and Resources, an office that keeps track of student groups, reported Wednesday that there is no official student-led animal rights organization on campus, and they had not even heard of any recent advocacy activity. ALF said it does not recruit on college campuses.

A spokeswoman for the UCSC tree-sit demonstration outside one of the buildings where animal testing is conducted said she does not believe her group was involved in Sunday's incident. While tree sitters, who are opposed to the university's geographic expansion plans, have expressed strong opposition to a new biomedical facility, Jennifer Charles said animal advocacy "is certainly not our main issue."

Peter Young, an animal rights advocate who returned to Santa Cruz County just weeks ago after serving prison time for setting minks free in the Midwest, said he didn't know how connected Sunday's contingent of protesters may be to other animal liberation groups and said he doesn't know who the protesters are.

Camille Hankins, an ALF press officer in New York, said her group operates by a strict creed not to harm humans or animals during advocacy activities, but said agents have destroyed millions in property and committed arson to make a point or liberate animals. She said "loud banging at the door" does not constitute a crime and that protesters wear masks as a precaution against being wrongly accused of assault.

"It's easy to get over-enthusiastic when you have a message to deliver," she said. "When we talk about terrorism -- terrorism is what goes on in a vivisection lab. More than likely people have tried to reach out and talk to [UCSC biomedical researchers] in an above-board way" before Sunday's incident.

The researcher whose home was targeted said protesters never contacted her about her work, which she said does not harm mice. Weeks before the incident, the sidewalk or driveways in front of several UCSC biomedical researchers' homes were scrawled with chalk decrying alleged animal abuse.

Contact J.M. Brown at 429-2410 or jbrown@santacruzsentinel.com.