EUSTIS, Fla. (AP) _ A group of vampire-obsessed teens drank each other's blood and talked about killing a friend's parents the night the couple was bludgeoned to death, a witness said Wednesday.

``I was disgusted. But I didn't understand why they wanted to kill them, so I didn't believe them,'' Shannon Yohe told The Associated Press.

Yohe, 16, was named in an affidavit released Wednesday, after one of the suspects charged in the Nov. 25 murder of Richard and Ruth Wendorf made her first court appearance in Florida. Dana Cooper, 19, of Murray, Ky., was denied bond.

The Wendorfs' 15-year-old daughter, Heather, and three other teens from Kentucky also are awaiting extradition from Baton Rouge, La., where they were arrested on Thanksgiving.

One friend told investigators that Heather ``wished her parents were dead'' while another recalled her saying she hated them, the affidavit said.

The affidavit also said that weeks before the slayings, Heather had asked her 17-year-old sister, Jennifer, if she had ever considered murdering their parents. Jennifer Wendorf told investigators about the conversation soon after the bodies were found at the family home in Eustis in central Florida.

Investigators believe the teens became attracted to vampires because of a bestselling role-playing game they took literally, drinking their own blood and that of animals they had mutilated.

Yohe told investigators that the four Kentucky teens visited her home in Eustis and talked about murdering the couple. One of them also called Heather Wendorf to get directions to their home, according to the affidavit.

In the interview, Yohe said she was close friends with defendant Roderick Ferrell, 16, who had moved to Kentucky from Eustis.

``When I knew him, he was a little weird, but nice. I thought I knew him,'' Yohe said. But when he came visiting with his friends, his arms were slashed and he began rummaging through her kitchen for a knife.

``He took one and slit his arm, and I was like, `Oh my God,''' she said.

Ms. Cooper sucked the blood from his arm; ``Then they started talking about where the best places to cut were, which parts taste best. I was like, `Get out of my house.'''

A short time later, she said, Rod began talking about murdering the Wendorfs in order to steal their car.

Police say the teens killed the couple and drove the car to Louisiana.

Ms. Cooper, Ms. Wendorf, Ferrell and Scott Anderson face first-degree murder charges. Sarah Remington is charged with being an accessory to murder.

Days before Anderson disappeared, his mother said he was shaking uncontrollably and she took him to a mental health counselor to be treated.

``He said, `Mamma, I'm losing my cookies,'' Martha Anderson said Wednesday before breaking into tears outside Juvenile Court in Baton Rouge, La.

Mrs. Anderson wants to tell the juvenile judge to order a mental evaluation for her son and give him a chance to tell his side of the story.

``He fell under the spell of something,'' she said. ``I don't know what it is.''