(Update: Missing UVA teen spent hours before disappearance with friends)

Police continued to search this college town for a fifth day Thursday, looking for any sign of the 18-year-old student who disappeared while walking alone after drinking with friends last weekend. Seeking the public’s help, authorities released a description of a man who a witness said approached the student in an off-campus pedestrian mall.

The unidentified man reportedly spoke with Hannah Graham shortly after 1 a.m. Saturday and put his arm around her as she walked along the Downtown Mall on East Main Street, a row of stores east of the University of Virginia’s main campus. Police want to speak with the man and consider him a “person of interest” but as yet have given no indication that he is directly connected to Graham’s disappearance.

Graham, a U-Va. sophomore who graduated from West Potomac High School in Fairfax County, was seen on surveillance videos at several locations on a mile-long route through Charlottesville on Saturday. She walked by an Irish pub, was seen hurrying past a Shell station, and then ultimately walked by downtown businesses as she headed east.

In one of the videos, from an Italian restaurant, a man is seen walking ahead of Graham. He pulls into a recessed store doorway, waits for Graham to pass, and then starts following her. Just minutes later, Graham is seen on a jewelry store’s video walking east with the same man a few steps behind her. That is so far the last video evidence of Graham’s whereabouts that police have made public.

Charlottesville police have identified a "person of interest" who they believe was in a bar with 18-year-old University of Virginia student Hannah Graham shortly before she went missing. Authorities describe the man as a black male, 32, who is 6-foot-2, 270 pounds and has dreadlocks. (Charlottesville Police Department)

After police released the surveillance footage, the witness came forward to report that he was the man seen following Graham in downtown Charlottesville. The witness, who lives in Charlottesville, told authorities that Graham was walking alone shortly after 1 a.m. and looked as if she was in distress. He said he began following her until another man approached her and began chatting with her.

“He said the man came up and put his arm around her and they were interacting,” said Charlottesville Police Capt. Gary Pleasants, describing the witness’s account. “He said it looked like someone she knew, so he walked away.”

Police said the witness described the man as black, 5-foot-10 to 5-foot-11, 250 to 285 pounds, with a close-shaved head, goatee and a slight “beer belly.” He was described as being in his late 20s to early 30s and as wearing black jeans and a white T-shirt, police said.

The unidentified man walked at least a few blocks with Graham shortly after 1 a.m., police said. Graham last texted friends at 1:06 a.m. — likely moments after she was last on video — to say that she was lost, according to police.

Graham was reported missing Sunday after friends said they had not heard from her since midnight.

Pleasants said the surveillance videos released by police do not show the unidentified man. He said the witness contacted police through a hotline, on which police had received 100 tips. He did not release the name of the witness, who he said played phone tag with investigators before voluntarily coming to the police department around 10 p.m. Wednesday.

The U-Va. community was rallying around the search Thursday, clinging to hope that Graham might be found alive.

Students held a candlelight vigil at the U-Va. amphitheater on campus Thursday night. Student council members passed out boxes of tissues and pink Starbursts, Graham’s favorite confection.

More than 2,000 students gathered in honor of the student who friends said has a spunky, spontaneous sense of humor. As a member of the ski team, she bowled friends over heading down the mountain wearing a flapper dress and draped in a Union Jack flag, a nod to her British heritage, said the Class of 2017 president, Abraham Axler.

“We miss you,” said student Lani Galloway, who spent spring break last year with Graham building houses in Tuscaloosa, Ala.

Addressing Graham directly, Galloway asked: “Where are you? We want you back where you belong.”

The ceremony ended with the students rising from their seats to sing the school’s “Good Old Song” alma mater, swaying arm and arm.

Finally, they all departed with hugs, some wiping tears from their cheeks.

Graham’s case cast a pall over the Downtown Mall, a pedestrian-friendly thoroughfare lined with an eclectic collection of coffee shops, family-owned restaurants and upscale bars with outdoor patios. Known as the beating heart of the historic town, the area is considered one of the safest places for college students to gather. On the surveillance videos, several people pass through the frames on the brightly lit concourse.

Dave Taylor, owner of the Read it Again Sam book shop, said that Charlottesville police had not come to his business seeking camera footage as of late Thursday. His storefront is one of the last places Graham is seen walking, captured by an exterior camera at Sal’s Caffe Italia across the street.

Taylor said members of the community had pushed the City Council to install more cameras in town. The mall is equipped with powerful outdoor WiFi stations but not an abundance of security cameras.

As soon as Frieda Loose-Wagner heard that Graham was last seen heading east through the downtown mall, she immediately began searching through surveillance footage at her family’s jewelry store.

“We need to be proactive,” Loose-Wagner said. “We need to get back to helping each other.”

Not long after scrolling through her footage, Loose-Wagner found the last-known, grainy images of Graham, walking past the store.

“We heard that we’re the last ones to see her on camera,” Loose-Wagner said. “It’s emotional. It’s sad and happy at the same time. Happy that you can see her alive. Sad because we haven’t found her.”

Police continued their search Thursday in an expanding area by the mall and down toward a nearby river and train tracks. Members of the U-Va. community were planning to conduct a massive volunteer search on Saturday, more than a week after Graham was last seen.

Graham’s disappearance has perplexed her friends and family, who described her as a conscientious student who was in regular contact. She was an accomplished jazz saxophonist in high school and was on the U-Va. ski team.

On Friday night, Graham was doing what many college students across the country do on the weekend: She ate dinner with friends and drank alcohol. After dinner, the group made plans to meet up again later. It is unclear why Graham was walking by herself or where she intended to go.

St. Martin reported from Washington. Julie Zauzmer in Washington contributed to this report.