Virginia police say they have set their sights on a "person of interest" in the investigation into the disappearance of 18-year-old Hannah Graham.

The suspect was seen buying a drink with Graham, a University of Virginia student, moments before she vanished on Saturday, Sept. 13 in downtown Charlottesville, the New York Daily News reported.

Investigators detained the 32-year-old man for questioning on Friday and searched his car and Charlottesville apartment, however there was no probable cause to make an arrest, police told the newspaper.

"We know who he is. We know where he is," Charlottesville Police Chief Timothy Longo said Friday, hinting that police will talk to him again. "I'm not fond of the term 'person of interest'...but let me just say this: we are interested in him," Longo said according to the Daily News.

The suspect, said to be a black man with dreadlocks, was seen on a surveillance camera walking with his arm around Graham by an outdoor mall at around 1 a.m. Saturday.

The two were seen entering a bar along the mall. The man ordered a drink and the two left, according to witnesses. Police believe the man drove away with Graham in a dark orange 1998 Chrysler coupe.

"My point is this, people saw Hannah and people saw him, and people saw them together," Longo said before urging the public to come forward if they remember seeing the vehicle, CNN reported.

Graham, of North Virginia, left a gathering of friends at a Charlottesville apartment complex at around 11 p.m. Friday before she disappeared. She texted her friends at around 1:20 a.m. Saturday saying she was lost.

The 5-foot-11 teen with blue eyes was last seen that Saturday morning on the downtown mall. Police say she might have been under the influence of alcohol and was therefore vulnerable, CNN reported.

On Thursday night, about 2,000 students attended a candlelight vigil held on campus for Graham. Her parents, who attended the vigil, expressed gratitude for the widespread support during this trying time.  

"We were comforted by the evident high esteem in which our cherished daughter is held by her many friends at the University of Virginia and beyond," John and Sue Graham said according to CNN.

"We continue to be optimistic that Hannah will be returned safely to us."