The owners of the 3-foot giant rabbit named Simon, who died on a United flight from London back in April, are threatening to sue the airline for damages. The group is also demanding an independent investigation of the incident and that the airline re-evaluate its standards and practices when transporting animals.

Simon, a Continental Giant rabbit, was bought by a group of investors in Iowa in hopes that he would win the Iowa State Fair’s world’s biggest rabbit contest. The contest would raise money for the Blue Ribbon Foundation, which works to renovate and preserve Iowa’s historic fairgrounds.

Unfortunately, Simon died following a flight from London to Chicago. However, the details of his death are vague.

Guy Cook, an attorney representing Simon’s owners, said at a press conference on Monday that Simon was reportedly locked in a freezer for up to 16 hours, accidentally, before boarding a connecting flight from Chicago to Kansas City.

United denied this claim in an email to The Des Moines Register, saying that “Simon arrived in Chicago at 10:25 a.m. and was seen moving in his crate about a half-hour later. A short time later, an employee found the rabbit motionless and determined he had died. At the time, Simon was being kept in a PetSafe kennel facility kept at 70 degrees Fahrenheit.”

However, to make matters worse, Cook also said United had the remains of the rabbit cremated without permission of the owners.

“United Airlines has essentially done nothing to demonstrate objectively what actually happened here,” Cook said.

The lawsuit demands that United not only pay for the purchase price of the rabbit and shipping costs, but also the “economic loss” of the animal, since Simon was meant to be a key fundraising attraction for the Iowa State Fair. The lawsuit gives United seven days to respond before filing.