A suspect, Luis Mendonca, was arrested on the scene. But while in handcuffs, DeCarlo was seen on a video surveillance camera beating Mendonca with his flashlight and foot.
DeCarlo was eventually found guilty of assaulting Mendonca.
But a judge overturned the conviction, finding there was prosecutorial misconduct in the closing arguments at trial.
DeCarlo remained at the Providence Police Department, suspended without pay.
But recently, he agreed to give up his job.
Last fall, the city and DeCarlo reached a separation agreement.
"He did not get any benefits in severance or anything of that nature. It was in his interest and the city's interest and that has been executed," said Providence Public Safety Commissioner Steven Pare.
Pare also said DeCarlo was not eligible for a city pension.
A civil suit filed by Mendonca against the city is still pending. He's seeking $7 million for the injuries he sustained while being in police custody.?