Police searched the Los Angeles County home of Paul Flores, who authorities said was the last person to see Smart alive. Tony Cipolla, a spokesperson for the sheriff's office, told CNN they recovered "some items of interest" in the case.
Police added they won't be discussing any details on items sought or recovered during the search.
Smart, of Stockton, Calif., vanished when she was 19. She had been to a party and was returning to a dorm at California Polytechnic State University in San Luis Obispo. Police said she was seen with Flores, who also was a student at the time. He was never charged or arrested.
Flores’ home near the Los Angeles harbor was among four locations in California and Washington state where search warrants were previously served in February.
In January, Kristin Smart's mother was told by a former FBI agent to be prepared for news and to secure a family spokesperson, according to the Stockton Record. The family later said that a former agent for the bureau had reached out.
Investigators also conducted digs at the California campus in 2016.
"This continues to be an active and on-going investigation," police said on Wednesday.
Fox News' Edmund DeMarche and the Associated Press contributed to this report