The Supreme Court sided with a prisoner's handwritten appeal on Wednesday, ruling in a unanimous opinion the federal government can be sued in abuse cases involving federal prison guards.

The Associated Press reported that the opinion, written by Justice Clarence Thomas, will allow Kim Millbrook to proceed with his lawsuit, stemming from an alleged sexual assault in 2010.

According to Courthouse News Service, Millbrook's suit, which he filed without an attorney, accuses three guards at the federal prison in Lewisberg, Pennsylvania, of leading him to a separate basement unit, then forcing him to provide oral sex while holding him by the neck.

Millbrook said the attack violated the Federal Torts Claim Act, which disqualifies federal employees from immunity in civil suits for deliberate actions. The government said an internal investigation and medical examination debunked Millbrook's accusations, while the 3rd Circuit Court of Appeals ruled in April 2012 that the law only applied when authorities are making arrests, conducting searches or seizing evidence

"The plain text confirms that Congress in­tended immunity determinations to depend on a federal officer's legal authority, not on a particular exercise of that authority," Thomas wrote. "Consequently, there is no basis for concluding that a law enforcement officer's intentional tort must oc­cur in the course of executing a search, seizing evidence, or making an arrest in order to subject the United States to liability."

The New York Times reported in October 2012 that Millbrook, who was originally convicted in 2007 on drug and gun-related charges as well as intimidating and tampering with witnesses, has filed three prior lawsuits, alleging mistreatment at each prison he has been jailed in.

The opinion can be read in its entirety below.

Millbrook vs United States

["Man in a cell" via Shutterstock]