Detectives in Gainesville are searching for University of Florida freshman Christian Aguilar, a South Florida native, who has been missing for nearly three days.
Police on Sunday said they suspect foul play.
Aguilar's family left their home in Southwest Miami Dade Friday to join the search at the university along with police.
"I'm in agony right now," said Carlos Aguilar, the teen's father. "People think I'm crazy, but I'm going to do the unthinkable to recover my son."
Aguilar, a graduate of the Doral Academy, was involved in a dispute about a girlfriend with another young man who beat him up, according to his father. The young man, who Gainesville police identified as 18-year-old Pedro Bravo, allegedly dropped Aguilar off near a field on campus after beating him up.
Carlos Aguilar and his family have been searching through the wooded areas of Gainesville.
Police have not released any further information about the other young man. Aguilar's father said he was questioned by detectives but declined to comment further.
Aguilar, 18, has not had a history of running away, according to his family.
"I know the longer it takes for finding my son, the chances are less for my son to survive," his father said.
Bravo has not been charged with a crime, but has been held for psychological examination since Friday under Florida's Baker Act, after telling investigators he wanted to harm himself.
Anyone with information is asked to call the Gainesville Police Department at 352-393-7659.