NEW YORK (AP) More than 50 years after Frank Serpico testified about endemic corruption in the New York Police Department, the department finally recognized his service and injury in the line of duty with an official certificate and inscribed medal of honor.

The former undercover detective, 85, received the honor in the mail Thursday, the New York Daily News reported .

Serpico testified in December 1971 to a panel appointed by Mayor John Lindsay to investigate police corruption, breaking the blue wall of silence, the protection that fellow officers sometimes give each other, such as refusing to testify.

Al Pacino went on to portray him in the hit 1973 movie Serpico, and his story is also relayed in a book by Peter Maas.

Current Daily News and former Associated Press reporter Larry McShane interviewed Serpico in December about the 50th anniversary of his appearance before the Knapp Commission.

I felt that finally I was going to tell the world and nobodys going to interrupt me, Serpico told the newspaper, speaking from his home in upstate New York. I thought, I know the truth. ... Every single word was mine, and it came from the heart.

Serpico was shot in the face during a drug arrest in Brooklyn in 1971 months before he testified and has maintained that the other officers he was with never made a call for an officer down.

While the department gave Serpico a medal recognizing his injury in 1972, it was handed over without ceremony or the accompanying certificate, he told the newspaper.

Mayor Eric Adams responded to the coverage, saying Serpicos bravery inspired my law enforcement career. Frank were going to make sure you get your medal.

On Thursday, Serpico tweeted a photo of the framed medal of honor and certificate that reads in part, in recognition of an individual act of extraordinary bravery performed in the line of duty.

He has continued to speak out against corruption and abuse by the police since his retirement in 1972 and says he has supported and listened to other whistleblowers over the years, including those who testified about the now-terminated stop-and-frisk policy .

In 2017, he publicly supported quarterback Colin Kaepernick, who protested against racial injustice while playing in the NFL.