Louisville, KY-- Police believe the man was murdered, but a cause and manner of death won't be known until Monday at the earliest.
The man was identified as 48-year-old Adan Fabian Perez, a native of Guatemala. He was a groom at the track. His body was discovered in barn No. 8 by a track security officer shortly before 5 a.m. ET, said Alicia Smiley, a Louisville Metro Police spokeswoman.
Churchill Downs spokesman John Asher said track officials know little more than the details released by police, but no changes are planned to security on the backside.
"We have no reason to believe it's not an isolated thing at this point," Asher said.
No arrests had been made as of Sunday afternoon.
Jo-Ann Farmer, the chief Jefferson County deputy coroner, said Perez's 19-year-old son, who also works at Churchill Downs, identified his father.
Marc A. Guilfoil, deputy executive director of the Kentucky Horse Racing Commission, said the man who died was a groom for trainer Cecil Borel. He lived on the backside and had been licensed by the commission since 2008, Guilfoil said.
Guilfoil said the commission's security director, Chris Clark, aided police Sunday by providing a database of workers licensed by the state.
According to an account Guilfoil said was relayed by Clark, the man was involved in a fight on the backside around 12:30 a.m. Sunday. At some point after that, a second incident apparently took place, Guilfoil said.
Police declined to describe the wounds or overall condition of the body. Smiley said the man was not in a horse stall, but she wouldn't say any more about where he was found.
Rob O'Connor, who trains horses at Churchill Downs, said in a telephone interview that the body was found in a barn he shares, but he declined to comment further because the investigation is ongoing.
Smiley said an autopsy is scheduled for Monday.
The Churchill Downs backside includes 48 barns and workers' dormitories, and some employees of individual trainers live in tack rooms in the barns, Asher said.
"It's a little city, 24 hours a day there," Asher said.
To work on the backside, workers must be licensed by the Kentucky Horse Racing Commission, Asher said.
While no Derby horses were in Barn No. 8, it is four away - about 150 yards - from where this year's winner, I'll Have Another, was stabled leading up to the race.
Police said Perez's death does not appear to be linked to the Derby.
"The timing would be unfortunate on any date on the calendar," Asher said.
The backside was quiet Sunday afternoon as workers washed horses, forked hay into piles and relaxed. With races resuming Thursday, trainers were scarce around the barns.
The death was the second on the Churchill Downs backside in about a year. Shortly after last year's Derby, 24-year-old jockey Michael Baze was found dead in his car after what was ruled an accidental drug overdose.
The Rev. Ken Boehm, chaplain at the track, said he hadn't spoken with any backside workers about Sunday's death but expected it will be mentioned at a regularly scheduled Monday night worship service.
"We're praying for family and friends. ... Certainly our thoughts and prayers are with them," Boehm said.