NASHVILLE, Tenn. (WKRN) — During the 12-year period between 1986 and 1998, there were three Tennessee State University students who vanished without a trace, and whose disappearances remain unsolved.

Then 20-year-old Alice Mae Sullivan was a sophomore business major at the historically Black university in Nashville in 1986. According to investigators, Sullivan moved to Nashville from Gallatin and was living at Town Terrace Apartments with her young son and boyfriend.

She left for school around 8 a.m. on Aug. 28, 1986, and was supposed to return home around 1 p.m., but hasn’t been seen since that morning. Investigators know that Sullivan attended classes in the morning hours, but much of the timeline in-between remains unclear.

She was last seen around 10 a.m. in one of her friend’s dormitory rooms in Hankal Hall. Her friend told police Sullivan was alone in her room when she left for her own classes. Sullivan may have also been spotted walking near the university’s Gentry Center that day.

Her parents traveled to Nashville the next day to report her missing after Sullivan’s boyfriend told them she hadn’t come home. Sullivan was close with her parents, who have previously stated that they don’t think she would have left without warning.

Police suspect that there may have been foul play involved in her disappearance, but have not officially named any suspects, despite there being a few people of interest in the case.

Now, 37 years since Sullivan disappeared, Metro Nashville Police Cold Case Detective Matthew Filter said in an email there have been no new tips or developments. But Sullivan is not the only TSU student whose disappearance remains unsolved.

Then 20-year-old Donald Johnson vanished just a little over three years later. Although an enrolled student, Johnson was suspended from attending classes because of financial problems. He was last seen at Boyd Hall, a dormitory on the university’s campus, on Nov. 18, 1989.

About nine years passed before the next unsolved disappearance. Marcus Rutledge, a 23-year-old senior at TSU, was reported missing by his girlfriend on June 8, 1998, after she was unable to get ahold of him and couldn’t find him at his apartment on Park Dale Drive.

Investigators said his dog was found shut in the bathroom with no food and only the toilet to drink from, which was out of character for Rutledge. His car, a 1995 Plymouth Neon, was found about a month later in an apartment complex on the west side of Nashville.

No one has heard from or seen Johnson or Rutledge since. All three cases remain open, with the students now close to or in their 50s. Sullivan, who would be 57 years old today, was wearing black jeans, a white shirt and a black silk jacket when she was last seen.

She is 5 feet 2 inches tall, weighs about 90 pounds and has black hair and brown eyes. Anyone with information on any of these cases is asked to contact the MNPD at 615-862-8600 or Crime Stoppers at 615-742-CRIME (615-742-7463).