For the second time in as many months, animal-rights advocates are criticizing the University of Utah for the accidental death and alleged mistreatment of animals during campus laboratory procedures.

PETA, or People for the Ethical Treatment of Animals, filed complaints Wednesday against the Salt Lake City school with the U.S. Department of Agriculture and the Office of Laboratory Animal Welfare, or OLAW.

The PETA complaints to federal authorities, co-signed by the group Students for Animal Welfare, highlight several instances since 2015 on the Utah campus in which laboratory animals were accidentally killed, or euthanized using allegedly unapproved and improper methods.

“Apparently whatever corrective measures the university keeps putting in place are just not working,” said Jeremy Beckham, a Utah-based PETA research associate. “Most animal research facilities in the country have clean inspection reports. The U. of U. just seems like they have violations over and over.”

U. officials, meanwhile, issued a statement late Tuesday saying the school remained ”devoted to ensuring the humane care and use of laboratory animals in our research programs.” Issues raised in the complaints, a U. spokeswoman said, had already been addressed.

PETA’s complaints include five instances of animal death, including two rabbits in October 2015, a marmoset in December 2015, two groups of mice killed between May 2016 and January 2017, and a lamb in April 2017.

The marmoset, lamb and one group of mice were not intended to die, Beckham said. And while the rabbits, the second group of mice and the lamb were intentionally euthanized, he said their deaths were brought about through unapproved protocols and in violation of federal guidelines.

“Over the last seven years or so, we’re approaching 15, 16 violations,” Beckham said. “Some of them are now critical, where animals are really being tortured to death.”

Of the animal incidents listed in PETA’s complaints, only the marmoset overlaps with a letter sent to the USDA last month by another group, Stop Animal Exploitation NOW!, or SAEN. Based in Ohio, SAEN urged federal regulators to fine the U. over the deaths of the marmoset, a macaque and a rabbit.

“This is no longer a single isolated incident,” SAEN co-founder Michael Budkie said at the time. “Negligence at the University of Utah has now killed three animals. That demonstrates a significant pattern.”

U. officials previously confirmed the deaths of the marmoset, macaque and rabbit cited in the SAEN complaint. Campus administrators had not yet received a copy of PETA’s documents late Tuesday, but spokeswoman Julie Kiefer in a written statement said the U. is committed to carrying out exceptional research to advance veterinary and human medicine, health and well-being.

“We recognize that high-quality science and humane animal care are inseparable, and we are devoted to ensuring the humane care and use of laboratory animals in our research programs,” Kiefer said. “Among other stringent measures, a board of experts rigorously reviews each animal study and a devoted team of veterinarians and professional staff monitors every animal, every day.”

The U. was provided with a summary of the incidents included in PETA’s complaint. Kiefer did not comment specifically on those incidents, but did not deny or rebut the animal-rights organization’s timeline.

“The university takes its responsibilities seriously, and self-reports all infractions and implements corrective actions immediately,” she said. “Although incidents are extremely rare, we are committed to reducing the number to zero and ensuring humane animal care for every research study.”

The new allegations by PETA raise the number of known incidents involving animals substantially, including roughly 50 mice.

Beckham said the U. was given an official warning last year stemming from the burning death of the macaque listed in SAEN’s complaints. A warning of that type is “exceptionally rare,” he said.

“To get to that official warning means you have to have serious repeat violations of the Animal Welfare Act,” he said.

Beckham said information in the latest complaint was drawn from the U.’s self-reporting of the incidents to OLAW, which oversees compliance with federal grants. But there’s no indication, he said, that the animal deaths were reported to the Animal and Plant Health Inspection Service, or APHIS, a department of the USDA which reviews violations of the Animal Welfare Act.

“The University of Utah needs to start to step up and start holding its faculty members accountable when they repeatedly break the rules,” Beckham said.

PETA is asking OLAW to reopen its previous investigations of the five U. incidents, citing a pattern of alleged misconduct and additional information stemming of repeat violations.

In its complaint to APHIS seeking an initial investigation, the organization includes only the rabbits, lamb and marmoset. Beckham said research involving mice is not regulated under the Animal Welfare Act.

“Unfortunately, you can do anything you want to mice and rats,” he said, “and it’s never a violation of the law.”

Kiefer said it is standard procedure for the campus to self-report to OLAW, which then reports incidents to APHIS for review.

“The university proactively implemented corrective actions to prevent any future infractions,” she said. “These corrective actions were subsequently reviewed and accepted by OLAW.”