Police questioned a man about a missing 19-year-old college student but said he is not a suspect in her disappearance.
The man was interviewed because he had given a ride home to Brianna Denison's friend the night Denison mysteriously vanished, police said.
"We have spoken with the person who was driving the Suburban that we were looking for originally and he is not involved in the case," Ron Holladay, a Reno police commander, said Wednesday in an interview with CBS' "Early Show."
Denison was last seen at 4 a.m. Sunday. Police said she was sleeping on a couch near an unlocked glass door after a night of partying.
When her friends awoke later that morning, she was gone " but her clothes, purse and cell phone were left behind. Authorities have classified Denison's disappearance as a possible abduction.
"All the indicators are that Brianna has been abducted," Holladay said. "It is our sincere hope that she'll come walking in the door any minute, but the longer it goes, the less the chances are of that occurring."
Two of her friends, Jessica Deal and K.T. Hunter, said they started making breakfast Sunday morning when they realized Denison's personal items were still there.
"We started piecing together later that hour that everything was still there," Deal said. "There is no way she left voluntarily."
"Brianna was one of the most cautious and responsible friends I had," she told CBS. "She would never go anywhere without her phone and ... every time she went out she was always calling her mom.
"No, this is not in her character at all. She would never run away."
Investigators with search dogs canvassed neighborhoods looking for clues to Denison's whereabouts, but found nothing.
"We have not discovered any shoe prints, anything that might lead us to a direction that a suspect may have taken her," Holladay said.
"We have done extensive searches both with canines and also on foot and door to door, under houses, backyards, things like that and have turned up no clues."
Detectives were awaiting test results on whether a silver dollar-sized stain on the pillow Denison was using is blood.
Denison, who grew up in Reno, is a student at Santa Barbara City College in Santa Barbara, Calif. Friends and family say she was at home over the winter break and had planned to return to school this week.
In the hours before her disappearance, Denison had been party-hopping at venues associated with a weekend snowboarding event, police have said.
"I just hope that whoever did this is listening and knows what a great person she is and she doesn't deserve this at all," Hunter told a Reno television station Tuesday night.
"Hopefully whoever did this sees how hurt everyone is over it, might even feel an inkling of that and return Brianna."