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RENO, Nev. (AP) - The mother and friends of 19-year-old Brianna Denison told jurors Monday of their concern and then panic after they discovered she had vanished while sleeping on a friend's couch.

Bridgette Denison described how her daughter, Brianna, packed some clothes before heading to a friend's house on Jan. 19, 2008 to get ready for a concert.

The next morning, she received a call from her daughter's friend, K.T. Hunter, telling her Brianna wasn't in the house. It was followed by another call soon after.

"She was crying, pretty hysterical," Bridgette said of Hunter. "And she had said she looked further at everything in her apartment. She said there was blood on the pillow that Brianna was sleeping on."

"I told her to call 911, and I went to her house," she testified, according to the Reno Gazette-Journal's online edition.

Brianna Denison's body was found in a snowy vacant lot in south Reno under a discarded Christmas tree on Feb. 15. She had been sexually assaulted and strangled. Two pairs of women's thong underwear were tucked beneath one of her legs.

James Biela, a 28-year-old pipe fitter who trained in martial arts, was arrested nine months later. He is charged with raping and killing Denison, and sexually assaulting two other women near the University of Nevada, Reno in late 2007.

Prosecutors have said they will seek the death penalty if Biela is convicted of Denison's murder.

Denison, who grew up in Reno, was a sophomore at Santa Barbara City College in California. She was visiting her family and friends during winter break when she disappeared.

Several college students who had attended the concert with Denison also testified Monday that nothing unusual happened that night.

Jessica Deal said she and Denison stayed at Hunter's house after they attended a concert and party at a downtown hotel-casino. Deal said she went back to the house early because she had to work in the morning, and she didn't hear Hunter and Denison when they came home.

Deal said they initially weren't worried when they got up and saw that Denison was gone.

"We started noticing her cell phone was on the counter. It was vibrating; probably a text message," Deal said.

They saw a spot that could have been blood on a pillow, but thought initially it might have been from Hunter's dog.