SAN FRANCISCO, CA — A man who said he was a 2,000-year-old vampire who needs to drink human blood has been found guilty of second degree murder for slashing the throat of a San Francisco homeless woman and killing her.

Joshua Rudiger, a 22-year-old with a history of mental illness, was also convicted on lesser assault counts in three other knife attacks on homeless San Franciscans in

"Prey is prey," Rudiger told investigators.

1998, the San Francisco Chronicle reported on Tuesday.

"He believes he's a vampire; he says he needs it (blood) for vitality," Rudiger's court-appointed attorney, William Maas, told jurors before Monday's verdict. "Maybe it's all going on in his head."

Maas was not available for comment on Tuesday.

Rudiger said in a videotaped statement he was a 2,000-year-old vampire, and admitted attacking several homeless people including 48-year-old Shirley Dillahunty, who was killed as she slept in a doorway on Oct. 29, 1998.

"Prey is prey," Rudiger, who pleaded not guilty by reason of insanity, told investigators.

Three were found with their throats cut and the Chinese character for 'death' scrawled in blood on the pavement.

Dillahunty's death followed a string of attacks on San Francisco homeless people, who in at least three cases were found with their throats cut and the Chinese character for "death" scrawled in blood on the pavement nearby.

Rudiger was apprehended after allegedly slashing the throat of man in Chinatown. The victim, who survived the attack, pointed Rudiger out to police, who arrested him and found a bloody knife stuck in his belt.

Police investigators and acquaintances have said Rudiger frequently claimed to be a vampire, a samurai or a ninja warrior. In 1997 he pleaded guilty to wounding a former friend with a bow and arrow, after which he spent six months in Atascadero State Hospital.

During the next phase of his current trial, Rudiger's attorneys will try to prove that Rudiger is insane — which would allow him to be kept in a hospital indefinitely rather than imprisoned for 15 years to life.