No one saw how an elephant fatally trampled a circus trainer who was loading the animal into a truck, police said.

It was not clear whether the handler fell or whether an elephant had knocked him down Monday afternoon in the Memorial Coliseum parking lot as the Tarzan Zerbini Circus (search) was packing up, said Victor Hopkins, spokesman for the Allen County Sheriff's Department.

The circus identified the trainer as Pierre Spenle, 40, of Texas. Spenle had been the elephants' primary trainer for several years, said Larry Solheim, general manager of the circus.

"He babied these animals," Solheim said.

Solheim said investigators were seeking advice from veterinarians, animal behaviorists and other experts.

"We're trying to know if this was an accident caused by inquisitive elephants," he said.

Foul play was not suspected in the man's death, police said.

The circus was treating Spenle's death as an occupational accident, Solheim said.

"We don't believe from the behavior of animals it was a premeditated, aggressive killing," he said.

Police were called after a coliseum employee saw the trainer lying inside a semitrailer with the elephants and alerted other handlers working in the area, Hopkins said.

Solheim said Spenle was lying between two elephants when he was found.

Two other handlers had helped the man load two elephants onto the trailer but walked away to let their colleague latch one last gate to secure the animals, Hopkins said.

The elephants were calm as they ate inside the trailer, when the handlers returned to check on the man, he said.

The elephants remained inside the trailer, which was stuffed with bales of hay, while county police and animal control officers investigated the accident. The trailer was later driven back inside the coliseum.

The man's injuries included blunt force trauma to the chest area, Hopkins said, and he was taken to Parkview Hospital (search) in critical condition. He died at the hospital, and the investigation was turned over to the Allen County coroner's office, Hopkins said.

Coroner Jon Brandenberger said an autopsy was scheduled for Tuesday.

The U.S. Department of Agriculture, which regulates circuses through the Animal Welfare Act (search), is looking into the incident, USDA spokesman Darby Holladay said.

"We're trying to see if it has remotely anything to do with violations of the Animal Welfare Act," he said.

The Fort Wayne Mizpah Shrine temple (search) had hired the Tarzan Zerbini Circus to perform at the temple's annual circus over the weekend.

Elephants are the largest of all land animals, and depending on the gender and species they could reach 13 feet in height and weigh up to 6.5 tons, according to the Humane Society of the United States' Web site.

Captive elephants from 1990 to 2003 killed 65 people and injured 130, according to Circuses.com.