A police officer exceeded the limits of his qualified immunity when he repeatedly stomped a prone man in the groin, the D.C. Circuit ruled.

The victim of Officer Jeffrey Bruce's attack was fellow Officer Juan Johnson.

Johnson's "off-duty act of kindness to a stranger in distress landed him in the middle of a drug bust in which he was repeatedly kicked in the groin by a police officer who mistook him for a criminal," Judge Griffith explained.

Johnson unwittingly helped a stranger escape from "stick-up guys," who turned out to be police officers.

The stranger was Andre Clinton, who was running from police after selling drugs to an undercover officer.

When the police arrived, Johnson was unable to convince the officers that he was one of them, so he lay down on the ground. Bruce then put the boots to Johnson before realizing his mistake.

"A reasonable officer would not have kicked the surrendering suspect in the groin," Judge Griffith wrote. "Johnson ... spread his arms and legs in a manner announcing submission."

Griffith also wrote that Bruce should not have attacked Johnson's groin.

"Striking the groin is the classic example of fighting dirty," Griffith wrote. "From the schoolyard scrapper to the champion prizefighter, no pugilist takes lightly the threat of a hit below the belt."

Johnson reported passing blood in his urine after the incident.