A Circuit Court jury found Stobert "Toby" Holt guilty Tuesday of manslaughter, extortion and writing threats to kill or do bodily harm in the case of a missing Lakeland man.
Jurors concluded Holt killed his boss' son, Robert Wiles, who has been missing since 2008.
However, they acquitted Holt of kidnapping.
The 44-year-old Cocoa Beach man didn't react visibly as the jury's decision was read in the crowded courtroom.
Prosecutors argued Holt was to blame for Wiles' disappearance as well as for sending a $750,000 ransom demand. Wiles' body has never been found.
Jurors deliberated about two hours Monday evening and another two hours Tuesday morning.
Originally, Holt was charged with first-degree murder. However, the jury found him guilty of the lesser charge of manslaughter.
Holt faces a maximum of 45 years in prison. Sentencing is scheduled for March 9.
Shortly after the verdict was announced, members of Wiles' family hugged and cried together outside the courtroom amid television cameras and reporters.
Tom Wiles, Robert Wiles' father, said he was pleased with the jury's decision.
"A bunch of people agree what this SOB did, and that's a good thing," he said. "A lot of people can recognize that now. But it doesn't bring my boy back."
He said the jury's verdict reaffirms what he already knew: His son is dead and Holt is responsible.
Wiles said he hopes Holt will someday reveal the location of his son's body.