Missing University of Virginia student Hannah Graham was followed by a man as she walked along the Downtown Mall in Charlottesville on Saturday morning, according to newly discovered surveillance footage from the area.

Charlottesville police told CNN that the same man later contacted officers and said he followed the 18-year-old girl because she looked agitated. He also said he saw Graham with another man and that it looked like she knew him. However, police have not been able to locate the second man on the surveillance footage, CNN reported. They are now searching for the second man.

Graham, a sophomore at the University of Virginia, disappeared early Saturday morning after leaving an off-campus party at a Charlottesville apartment complex. She left her friends at around 11 p.m. on Friday. By 1:20 a.m. Saturday, she sent her friends a text saying she was lost.

Police have recovered other surveillance videos showing Graham running alone near a Shell gas station. Other videos show the 5-foot-11 teen outside a pub and a downtown shopping mall, CNN reported. So far, the videos do not indicate she was being pursued and it remains unclear where she went, police told the station.

Scores of interviews have been conducted and police have increased the search area beyond east of the university. FBI, Virginia State Police and the Virginia Department of Emergency Management are aiding in the search, CNN affiliate WVIR reported.

As police continue their investigation, Graham's parents are growing more concerned that something terrible has happened to their daughter.

"Hannah is beyond precious to us," John and Susan Graham said Wednesday, according to CNN. "We are truly devastated by her disappearance. It's totally out of character for us not to have heard from her, and we fear foul play."