FBI agents investigating an alleged "human chop shop" say there were all sorts of ghastly sights when they raided an Arizona business.

That firm, the Biological Research Center, has since closed.

The FBI's findings are outlined in newly released court documents, Gizmodo reports, and they include "a bucket of heads, arms and legs" and a cooler filled with penises.

In one room, agents claim they found a woman's head sewn onto a man's body "in a ‘Frankenstein’ manner.”

In all, nearly 1,800 body parts were discovered.

One FBI agent told Reuters the discoveries were so disturbing that he now suffers from post-traumatic stress disorder.

A total of 33 people have sued the Biological Research Center, claiming bodies of their loved ones wound up in the business' possession as a result of "false statements." Many reportedly believed the bodies would be used for medical research, according to Phoenix TV station KTVK.

Selling body parts is illegal in most states, Gizmodo says.