WELLINGTON, Fla. " Organ by organ, veterinarians are taking apart 21 prized polo horses to uncover what killed them mysteriously over the weekend during preparations for a match in one of the sport's top championships. Simultaneously, state authorities have opened a criminal probe to determine whether the deaths were intentional, a result of negligence or simply a terrible accident.
With careful cuts to their muscular bodies, the investigators look for lesions, fluids, bruises and hemorrhages, any obvious signs of sickness. They're removing the hearts, lungs, livers, kidneys and spleens, and cutting small samples to be tested for toxins. The process unfolds much as it would for a dead person.
State officials believe the horses died from an adverse drug reaction, toxins in their food or supplements, or a combination of the two. Two days after the horses' deaths, authorities say they have not uncovered any crime but continue to investigate.
"We want to make sure from a law enforcement standpoint that there was no impropriety ... no purposeful harm or laws violated in Florida," said Terence McElroy, spokesman for the state Department of Agriculture and Consumer Services, which is handling the case with help from the Palm Beach County Sheriff's Office.
The horses from the Venezuelan-owned team began collapsing Sunday as they were unloaded from trailers at the International Polo Club Palm Beach, with some dying at the scene and others hours later. They were set to compete in the sport's U.S. Open tournament ahead of the finals this coming Sunday, and were seen as top contenders.
While veterinarians work with their scalpels, investigators are interviewing everyone who encountered the horses the day of the game and gathering evidence such as feed and supplements from the stables where the horses were kept.
"Should criminal activity surface, we don't want to be so far behind the eight-ball that we're playing catch-up," said sheriff's Capt. Greg Richter.
The exhaustive process included more evidence collecting Tuesday at the stables used by the Lechuza Polo team, said Dr. Michael Short, the state's equine programs manager who is helping coordinate the case.
The investigation hinges on a combination of interviews with players and groomers, tests of feed and a history of the horses' training regimens, Short said. Information gathered there and during the necropsies will help investigators refine their approach to the toxicologies.
Officials said the necropsies were completed by Tuesday night, and revealed some bleeding but offered no definitive clues. Short expects that testing blood and tissue for toxins will be more important in pinpointing the cause. But results from toxicologies could take weeks.
Short had said earlier in the day the necropsies may not reveal much, given officials suspect the culprit to be "some type of toxin or poison."
The team's owner, prominent Venezuelan banker Victor Vargas, has not spoken publicly since the deaths. In fact, it's unclear if Vargas, president of the Venezuelan Banking Association, or the team are still in Florida. Authorities would not say.
The team issued a statement Monday night that it does not know the cause of deaths, but is helping with the investigation.
While it's not clear exactly how the Lechuza horses were fed or trained, several people involved in the sport say that keeping the horses on a strict routine is a key to winning games. Trainers rarely stray, especially not hours before a match.
Kris Bowman, manager of the Vero Beach Polo Club, said the animals are generally given grain and hay in the morning, then in the evening and more hay around noon. Some ponies also are given electrolytes in their water, Bowman said.
"Everybody has their own style," he said. "Just like any athlete would have for a warm-up."
The teams spend months fine-tuning their daily routines, said Owen Rinehart, a polo player and breeder in Aiken, S.C., and it would be unusual for a successful team like Lechuza to deviate at the last minute.
"They certainly have done everything right in the past," Rinehart said. "I don't think that there's any way anybody would compromise a situation like that."
He said trainers for top teams wouldn't risk giving a potentially dangerous performance-enhancing drug to an entire group of horses. The 21 Lechuza horses have been estimated to be worth more than $2 million.
"It's just not worth it," he said.
However, the U.S. Polo Association doesn't require drug testing of horses.
"There are no rules," the association's director, Peter Rizzo, told the South Florida Sun Sentinel.
He did not return repeated calls from The Associated Press.
The club said games would resume Thursday with a moment of silence and a wreath laying ceremony. Finals are still set for Sunday. The Lechuza team has withdrawn.
Associated Press writer Sarah Larimer contributed to this report.