A sheriff on California's Central Coast plans to make a major announcement Tuesday in the nearly 25-year mystery of the disappearance of college student Kristin Smart.

San Luis Obispo County Sheriff Ian Parkinson scheduled a news conference at 2 p.m. at California Polytechnic State University in San Luis Obispo, where Smart was a student, to discuss “major developments in the investigation" into her disappearance.

The news comes about a month after the sheriff named former student Paul Flores as the “prime suspect” in the case and investigators searched his father's home and property in the city of Arroyo Grande, about 15 miles (24 kilometers) south of the university, using ground-penetrating radar and cadaver dogs.

An investigator uses ground penetrating radar to search the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)

An investigator uses ground penetrating radar to search the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)

Smart, 19, of Stockton, California, vanished in May 1996 while returning to a dorm at Cal Poly after a party. She was seen with Flores, who also was a student at the time.

Search warrants were served last year on Flores’ home in the San Pedro area of Los Angeles and at other locations in California and Washington state. Investigators conducted digs on the campus in 2016.

Flores has remained mum through the years, invoking his Fifth Amendment right to not answer questions before a grand jury and in a deposition for a lawsuit that was brought against him.

San Luis Obispo Sheriff's Office personnel dig in an area in the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)

San Luis Obispo Sheriff's Office personnel dig in an area in the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)

 San Luis Obispo Sheriff's Office personnel continue their investigation while searching in the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)

San Luis Obispo Sheriff's Office personnel continue their investigation while searching in the backyard of the home of Ruben Flores, Tuesday, March 16, 2021, in Arroyo Grande, Calif. Flores is the father of Paul Flores, who remains the prime suspect in the disappearance of Kristin Smart in 1996. (AP PhotoDaniel Dreifuss)