Police investigating the disappearance of a University of Virginia student have focused their search in an area of downtown Charlottesville where she was last seen on surveillance video walking alone in the early morning hours Saturday.

Hannah Graham, 18, was reported missing Sunday after friends said that they had not heard from her since after midnight on Saturday.

On Wednesday, more than three days after she disappeared, police shared two surveillance videos that show Graham walking in downtown Charlottesville after drinking and socializing with friends Friday night into Saturday.

The disappearance has perplexed Graham’s friends and family, who know the sophomore as a responsible and organized student. Her former teachers at West Potomac High School in Fairfax County, where she earned a diploma in 2013, said she has a dry wit and showed leadership on the softball diamond and poise as a top saxophonist in the school’s jazz band.

New evidence police released Wednesday shows Graham walking near a busy outdoor seating area at McGrady’s Irish Pub in Charlottesville, east of the main U-Va. campus. A second video shows her near a Shell gas station about four blocks from McGrady’s. She is seen running at the beginning of the video before slowing to a walk.

Charlottesville police released surveillance video of 18-year-old University of Virginia student Hannah Graham walking near Sal's Pizza in the early morning before she disappeared September 13. (Charlottesville Police)

Charlottesville Police Chief Tim Longo said that he did not think Graham was being followed when she was seen running in the footage.

At one point, video shows Graham walking near railroad tracks that cut through Charlottesville. Norfolk Southern spokesman Robin Chapman said the rail line owns the tracks and that between 20 and 25 trains, including four Amtrak trains, use the line in a 24-hour period.

After she passed the gas station, Graham went to an outdoor mall downtown, Longo said. He said that an eyewitness, one of more than 100 people who have called a designated tip line about Graham’s disappearance, had spotted her in that area and that police planned to examine additional surveillance camera footage.

Longo said Graham had been drinking alcohol with her friends on Friday night. They ate dinner together and made plans to meet up again later. Graham left, and it was the last time her friends saw her.

Longo said Graham is not thought to have taken any drugs, but he said the alcohol might have impaired her judgment and left her vulnerable.

Graham’s mother, brother and friends realized on Sunday that they had not heard from Graham during the weekend — which was unusual — and they contacted police Sunday evening. Police said that Graham’s last communication with friends was a series of text messages after 1 a.m. Saturday. One text indicated that Graham was lost and in unfamiliar surroundings.

The FBI is assisting in the case and police have used bloodhounds in the search. Longo said police took electronics from Graham’s off-campus apartment, which she shares with three roommates.

Longo said Graham’s disappearance is reminiscent of the case involving Morgan Harrington, a Virginia Tech student who was found dead months after vanishing from a concert in Charlottesville in 2009. Longo noted that police had already canvassed the area where Harrington’s remains were found. No suspect has been linked to Harrington’s death, and police have released no evidence of suspected foul play in Graham’s case.

“Both of [the disappearances] occurred within the proximity of the University of Virginia,” Longo said. “Both of them are young girls. I mean, it’s just that simple.”

On Tuesday night, Graham’s friends painted a well-known bridge in Charlottesville with the inscription “Bring Hannah Home.” In Fairfax, members of the West Potomac softball team painted a boulder in front of the school with the same message in bold letters.

West Potomac softball coach Craig Maniglia said Graham played all four years at the school and was a captain of the varsity team her senior year. An outfielder and consistent base hitter, Graham was known for her team-first attitude.

“From a coach’s standpoint she was a delight — never late, never missed anything,” Maniglia said. “Your best players sometimes go unnoticed because they don’t make mistakes. That was the kind of player she was.”

West Potomac band director Steve Rice said Graham was an accomplished alto saxophonist when she joined the band as a freshman. He said she was among a handful of young instrumentalists who played in a more advanced section as freshmen. She later served as the lead alto sax player in the jazz band.

“She was able to handle a really rigorous academic load along with being a great band kid,” Rice said. “She was able to handle it with grace.”

Graham’s family members went to Charlottesville this week and were doing whatever they could to help the search.

“I would add that we are trying to remain hopeful,” Graham’s father, John Graham, said in an e-mail to The Washington Post on Wednesday.