An inmate, publicly known as John Doe, alleges that police and prosecutors offered him favors in exchange for his testimony and instructed him to lie about those offers.

CNN reported that Doe helped secure a conviction in the United States’ oldest cold case murder trial in 1957. Doe said the police and prosecutors did not keep their promises to him after he gave them his testimony.

The man Doe testified in 2012 has since been freed. Doe’s concern in prison was that people would know he was a “snitch,” so his identity was protected by a court gag order. However, in a lawsuit he recently filed in Illinois, Doe alleges his identity was disclosed to other witnesses. CNN reported that his identity soon got out:

“Just days after his testimony, the women wrote thank-you notes to Doe in prison using his true name. His mail was screened by at least three prison employees, the suit states, and initially was delivered to the wrong cell and read by other inmates.”

After inmates and guards found out Doe’s identity, he said some guards said he had done “the right thing.” Doe was cornered by five inmates in a prison shower in June 2013. The inmates assaulted him until Doe “believed he would be stomped to death or rendered unconscious and defenseless, naked in the shower.”

After this assault, Doe was moved to another part of the prison. He was assaulted again and says he has continued to receive rumors and threats.

If Doe’s allegations are shown to be true, CNN reported that everyone involved in the prosecution of Jack Daniel McCullough could face severe consequences:

“Making promises to secure testimony from inmates is frowned upon because it severely diminishes their credibility. And violating a judge’s gag order can lead to a finding of contempt of court, punishable by sanctions that include jail time, fines or exclusion of the witness’ testimony.”

The defendants named in the lawsuit include a police investigator and prosecutor in McCullough’s trial. They are Special Agent Brion Hanley of the Illinois State Police and prosecutor Julie Trevarthen.

McCullough was convicted of murder and kidnapping of a 7-year-old who disappeared in Sycamore, Illinois in 1957. He was serving a life sentence until his conviction was overturned and he was set free.