The father of a missing University of Florida student asked the FBI to assist in the case Monday.
Weeks after Christian Aguilar's disappearance, police continue following leads, including those given by nearly a half-dozen psychics.
Police charged an 18-year-old with murder in the case.
Officer Ben Tobias announced that the Gainesville police department charged Pedro Bravo with the death of Aguilar. He did not offer further details.
The 18-year-old Aguilar was last seen about 6 p.m. September 20, according to a police statement.
His body hasn't been recovered, said Tobias, who urged the public to reach out to authorities with any information on the case.
"We would ... encourage property owners, residential or business, who may have lime rock roads on their property, that were accessible to the general public, to search those properties for any suspicious areas of ground that appear to have been disturbed," Tobias said. "We are also requesting information from anyone who may have seen a suspicious vehicle, likened to a Blue Chevy Blazer, in any remote areas on the night of Thursday, September 20."
Bravo told investigators that he'd gotten into "an altercation with Aguilar" on the night the college student went missing, police said. Bravo then left Aguilar in a parking lot in the central Florida city, prompting police to warn that Aguilar may be disoriented and/or seriously injured.
Aguilar's father told CNN affiliate WCJB that his son disappeared after a fight over a girl.
After talking with police September 21, Bravo was held for mental examination after threatening to harm or kill himself. He was later charged with depriving a victim of medical care, a third-degree felony.
Authorities have used helicopters and K-9 units to search for Aguilar, to no avail. The young man's family members, meanwhile, have plastered the area with fliers, taken to Twitter to generate leads and invited a nonprofit search group to help look for him alongside family members and police.
Gainesville police posted a fresh plea Friday night, on the department's Facebook page, asking volunteers to report to the Florida Farm Bureau at 9 a.m. Saturday to resume the search for Aguilar.
CNN's Joe Sutton and Greg Botelho contributed to this report.