RENO, Nev. – The family of a 19-year-old college student who mysteriously vanished from a Reno, Nev., home early Sunday morning is appealing to the public for information leading to her return, while police continue a nationwide search for her.
Brianna Denison, a student at Santa Barbara City College, was staying with friends near the University of Nevada, Reno. She was last seen at about 4 a.m. Sunday, when she returned home from a party and went to sleep on the couch wearing sweatpants and a T-shirt.
A spot of what appeared to be blood was found on her pillow. Police have sent it to the lab for testing. The couch where Denison was sleeping was in front of an unlocked glass door. Investigators believe she may have been abducted.
Denison's aunt, Rena Denison, said detectives are investigating her niece's boyfriend, according to KOLO-TV.
"Just awful," her aunt told KOLO-TV about the text messages Denison and her boyfriend exchanged the night she disappeared. "They were breaking up kind of stuff, saying awful things, calling her all kinds of names. He's just young and jealous."
The boyfriend was in Reno Friday night, but according to Rena Denison, was supposed to go back to college the next day, KOLO-TV reported.
But the commander of the Reno Police detectives division told FOXNews.com that Denison's boyfriend is not a suspect in the case and he was in Oregon the night she vanished.
"The aunt identified him as a suspect and that is just not true," said Cmdr. Ron Holladay. "He was of course very upset about that. ... At this point, we don’t have any reason to believe that he is a suspect in her disappearance."
The pair were text-messaging the night Denison was last seen, including "just prior to her disappearance," Holladay said.
Denison is a psychology student at Santa Barbara City College in Santa Barbara, Calif., and was back in her hometown of Reno for winter break.
In the hours before her disappearance, Denison had been party-hopping at venues associated with a weekend snowboarding event, including attending a rap concert at the Sands Hotel and Casino.
Police were searching for a 45-year-old man who gave a resident of the house where Denison was staying a ride home after one of the parties. The young woman had been trying to hail a cab when she approached the man at the casino and asked if he could drop her off. He was driving a tan-colored Chevy or GMC Suburban, but he did not come into the house.
Denison's family is offering a $100,000 reward for information leading to her safe return.
"From day one, it was love at first sight," her grandfather Bob Zunino told the Reno Gazette-Journal. "This little girl didn't forget birthdays, or a little note or anniversaries. ... If she's with someone now, we want her back. We want her back."
Police are hoping the media attention brought to the case will encourage anyone who may have seen something to report it, according to the newspaper.
"You never know who could have caught a glimpse of something," another aunt, Lauren Denison, told the newspaper. "This is a person's worst nightmare. This gives us fear, knowing the type of person she is. We adore her and want her back."
She told FOX News that her niece's disappearance was very unusual.
"If she could contact us, she would," said Lauren Denison, adding that Tuesday was a critical day in the search. "If anyone is watching, we are desperately wanting her back, no matter what. If anyone knows anything, please call the police department.'
Denison's friend K.T. Hunter told FOX News that it didn't initially occur to her and her housemates that something might have happened to Denison when they saw she wasn't on the couch Sunday morning.
"It didn't even cross our mind," said Hunter, who thought Denison went to sleep in her roommate's vacant room. "When we knocked on my roommate's door and she wasn't there, we knew something was wrong."
Hunter said there was no sign of a struggle, but they found a blanket Denison was using in the kitchen.
She said her friend's disappearance has been "a nightmare."
"At first, I didn't even believe it was happening," a tearful Hunter told FOX News. "As time goes on, I can't imagine another minute without knowing where Brianna is. Everyone just loves her so much."
Hunter told the Reno Gazette-Journal that the couch Denison spent the night on is against the wall of the bedroom where she was sleeping with her dog.
She said she never heard a noise and the dog never barked.
Hunter said Denison was sober the night she vanished, and had planned to pack Monday to go back to Santa Barbara.
Another friend made a public plea to the man who drove her home from the party to turn himself in for questioning.
"You know who you are," said the friend on FOX News. "You need to voluntarily talk to police."
Denison is described as white, 5-feet tall, 98 pounds, with long dark brown hair and blue eyes.
Investigators say she may have been wearing light blue or pink sweatpants, a T-shirt and no socks or shoes when she disappeared. Her purse and cell phone were found in the house, but a brown stuffed bear that she was using as an extra pillow is also missing, police said.
Holladay said the investigation has been challenging because of the lack of clues.
"It's really difficult going right now because we don't have a lot of forensics," he told FOXNews.com. "As far as hard evidence goes, it's very, very limited."
Investigators were looking into the possibility that Denison's disappearance is related to attacks against two female students at the University of Nevada, Reno, late last year.
Both women were grabbed from behind and sexually assaulted in the early morning hours in November and December. No arrests have been made.
The Associated Press contributed to this report.