A showdown at police headquarters.

Former officer and now private investigator Manuel Gomez has painted detective David Terrell as a rogue cop who he claims beat people and falsely arrested teens alleging they were gang members. 

"He gives all good cops a bad name. There is no reason why he should be on the job. He should be fired," Gomez said.

But detective Terrell says those are ridiculous accusations made against him by gang members suing the city. And he says Gomez is helping them and their lawyers to make a quick buck off of the city.  

"Everyone gave that guy the fired police officer all of the credibility in the world, which is sad," Terrell said.

This stems from the arrest of Bronx teen Pedro Hernandez for a 2015 shooting. The teen gained national attention while locked up on Rikers Island for over a year because he couldn't make bail. His case was eventually dropped. Gomez says he's the one that dug up info to help Hernandez and point a finger at Terrell as being corrupt.

"It makes me upset. I have a mother, I have brothers. I have aunts, and for someone to call you a terrorist and a corrupt cop with no facts whatsoever," Terrell said.

Terrell worked taking down gangs. He was caught on video playing Cee-Lo, rolling dice with alleged gang members, but he says all he was doing was proving to them he knew how to play.  The detective has now filed a federal lawsuit against Gomez and members of the media for defamation. He's also suing the Bronx DA, police commissioner and the mayor. He says they have not defended him against unfounded allegations. His lawyer, Eric Sanders, is claiming racism. 

"They protected the white employees, the Caucasian employees over David Terrell. They knew from the beginning he had absolutely nothing to do with this, nothing," Sanders said.

"My career is ruined at this point. Even if I get my stuff back, how can I go out there in the street when it is already, you can put my name in and it comes up as monster cop," Terrell said.

Terrell is on modified duty without his gun. He works in Manhattan criminal court inputting prisoners names. 

Terrell says he's getting a lot of support from fellow officers because he's speaking out. He also says he's continuing to help solve cases.

Because of his knowledge of gang members he says other cops call him for information. 

He says he's just waiting now, to have his day in court, to clear his name.