GALVESTON – Researchers at the University of Texas Medical Branch violated the law by allowing a monkey to escape, then euthanizing it after the animal was found to have a broken leg, an animal rights group alleged in a federal complaint.

Stop Animal Exploitation Now!, or SAEN, said Tuesday that it has filed a complaint with the U.S. Department of Agriculture, which is charged with enforcing animal-welfare laws. SAEN said the medical institution violated the law on animal handling.

SAEN said the monkey escaped from the National Laboratory, one of the most secure laboratories in the nation where deadly diseases like Ebola are researched, but UTMB spokesman Raul Reyes said the monkey did not escape from the National Laboratory. Reyes said the monkey escaped from an animal handling area, but was unable to specify where on the UTMB campus the handling area was located.

He confirmed that a monkey escaped from a cage Sept. 24, broke its leg and was euthanized. Reyes lacked any other details.

UTMB reported the incident as required to the U.S. Department of Agriculture, the National Institutes of Health's Office of Laboratory Animal Welfare and to a UTMB animal welfare committee, the spokesman said.

"Clearly there was another incidence of negligence at UTMB" said Michael Budkie, a spokesman for the animal rights group.

The SAEN complaint asks the USDA to impose the maximum fine of $10,000 per violation of the U.S. Animal Welfare Act.

"They can't even close a cage door properly," Budkie said. "Why should we believe they could do science?"

Reyes responded, "We treat them as humanely as possible," pointing out that the animals are part of research to find cures for some of the world's most dangerous diseases.

The complaint is the latest in a series filed by the group againt UTMB since a 2015 federal audit found that eight monkeys suffered painful deaths instead of being euthanized.

A former UTMB veterinarian also has filed a complaint with federal agencies alleging many more animals may have been mishandled, as well as a lawsuit claiming retaliation for his efforts to uphold animal welfare regulations. A USDA investigation into the deaths is ongoing.