According to a United Nations special rapporteur on torture, Nils Melzer, the untempered use of Tasers in U.S. prisons goes far beyond the realm of justifiably punitive. Nils says that in some cases, the “grave abuse” suffered by inmates is tantamount to torture. Melzer has called on U.S. officials to consider filing criminal charges against prison authorities in Ohio, Tennessee, Arkansas, and Oklahoma. A massive new Reuters investigation features video footage of 22 incidents Melzer says violate the U.N.’s prohibition of cruel and inhuman punishment.

“In my view all of the incidents shown in this video require independent investigation and most of them are likely to merit prosecution. Clearly gratuitous infliction of severe pain and suffering…constitutes a grave violation of human dignity and of the universal code of conduct for law enforcement officials,” Melzer told Reuters.

The use of Tasers has been the subject of debate for many human rights organizations, including Amnesty International and the ACLU. According to a report by the former, 500 people died at the hands of law enforcement using stun guns between 2001 and 2012. Since 2000, Reuters has been keeping tabs on the misuse and overuse of Tasers and has accounted for 104 inmate deaths. Even more disturbing, the majority of cases show that the victim was already restrained when they were tased.

Unfortunately, the numbers figure rather predictably into disturbing patterns of police brutality. For the time being, the use of Tasers in prisons and law enforcement continues to rise, even with a dearth of suitable training policies.