LOS ANGELES (AP) — The “prime suspect” was arrested Tuesday in the 25-year-old disappearance of a California college student and the San Luis Obispo sheriff planned to announce “major developments” in the case.

Paul Flores, 44, who was the last person seen with Kristin Smart before she vanished in 1996, was taken into custody in the Los Angeles area. His father, Ruben Flores, 80, was arrested as an accessory at his Arroyo Grande home, where sheriff’s investigators conducted another search.

Defense attorney Robert Sanger confirmed Paul Flores was arrested in the Smart case, though no details were immediately available on the charges he faces. Sanger declined further comment.

Ruben Flores was booked on suspicion of accessory after a felony, according to San Luis Obispo County jail records.

Smart, 19, of Stockton, vanished in May 1996 while returning to a dorm at California Polytechnic State University in San Luis Obispo after a party. She was seen with Flores, who was a student at the time.

Sheriff Ian Parkinson scheduled a news conference at 2 p.m. at the Cal Poly campus to discuss “major developments in the investigation” into Smart’s disappearance.

A spokesman for the Smart family said “this is an extremely emotional day” and they would issue a statement later in the afternoon.

The news comes about a month after the sheriff named Flores as the “prime suspect” in the case and investigators searched his father’s home and property using ground-penetrating radar and cadaver dogs.

Investigators served another search warrant Tuesday at the home of Ruben Flores about 15 miles (24 kilometers) south of the university on California’s Central Coast, KSBY-TV reported. They appeared to be disassembling a deck outside the home and the sound of power saws and drills could be heard whining in the background.

Search warrants were served last year on Paul 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.

Paul 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.

He was arrested in February on a weapons charge and released on bond.