Elon Musk’s brain implant startup, Neuralink, and the University of California, Davis, have been accused of “egregious violations of the Animal Welfare Act” by the Physicians Committee for Responsible Medicine (PCRM), citing documents obtained through a public records lawsuit.

The nonprofit — which successfully pressured U.S. medical schools including Johns Hopkins to stop using live pigs for surgical training — is asking the USDA to investigate the research facilities at UC Davis and Neuralink, saying the “carelessness by these facilities resulted in the suffering and death of several monkeys.”

Neuralink did not respond to a request for information from Medical Design & Outsourcing, but UC Davis said Neuralink researchers used facilities at the school’s California National Primate Research Center, with university staff providing veterinary care and monitoring of the monkeys. The university said the research protocols were approved by the UC Davis Institutional Animal Care and Use Committee, and that the research collaboration with Neuralink ended in 2020.

“We strive to provide the best possible care to animals in our charge,” UC Davis said in a statement. “Animal research is strictly regulated and UC Davis follows all applicable laws and regulations including those of the U.S. Department of Agriculture, which makes regular inspections, and the NIH Office of Laboratory Animal Welfare.”

In a letter to USDA, PCRM Animal Welfare Operations Director Robert Gibbens said a Neuralink-funded project at UC Davis to develop a large-scale brain-machine interface in rhesus macaques involved craniotomies for the implantation of electrodes into their brains.

The group said researchers failed to properly care for dying monkeys, failed to care for the psychological wellbeing of monkeys used in the experiment, and deviated from the approved protocol by using an unapproved substance called Bioglue that destroyed parts of their brains.

Records show monkeys were caged by themselves, restrained to a chair for up to five hours per day, and suffered infections, depression, weight loss, extreme gastrointestinal distress and physical trauma, including missing fingers. Some monkeys died during procedures, including device removal, PCRM said the records show.

PCRM is suing UC Davis for photos, video and animal disposition records from the experiments. The university has refused to provide them, saying it is not required to under the California Public Records Act.

“UC Davis may have handed over its publicly-funded facilities to a billionaire, but that doesn’t mean it can evade transparency requirements and violate federal animal welfare laws,” PCRM Research Advocacy Coordinator Jeremy Beckham said in a news release. “The documents reveal that monkeys had their brains mutilated in shoddy experiments and were left to suffer and die.”

Neuralink has released videos from its research for publicity purposes. One video shows a monkey playing video games; another features the robot developed to implant the electrodes.

Musk said in December that he hopes to have the devices implanted in humans as soon as this year.