The NYPD is considering filing departmental charges against its lead ticket-fix detective after discovering he leaked sensitive information to a former Internal Affairs cop who is now under indictment in the sweeping case, The Post has learned.

In a stunning breach that could cripple Bronx District Attorney Robert Johnson’s prosecution, Detective Randy Katakofsky divulged details of the investigation during several “inappropriate” conversations with Lt. Jennara Everleth-Cobb, who had transferred out of IAB at the start of the ticket-fixing scandal, law enforcement sources said.

“He was a little chatterbox. He was leaking like a sieve,” said one source.

NYPD brass is now deciding whether to hit Katakofsky with internal charges — which would likely torpedo his credibility.

Among the charges being considered, said a source, is “failure to follow department protocol.”

Katakofsky has allegedly admitted in meetings with his IAB bosses that he went rogue and shared information about the case with Cobb, who is one of 16 cops facing felony prosecution in The Bronx.

But he claimed he was conducting an “integrity test” — planting information with her to see if it surfaced elsewhere, the sources said.

“You can’t freelance like that,” blasted one law-enforcement source. “There is a central group in IAB [that conducts integrity tests]. It has to be coordinated.”

A source close to Cobb said, “She did not feel it was an integrity test. The information he was feeding her was very credible.”

Patrick Lynch, head of the PBA union — who has publicly slammed the Bronx probe, noting that ticket-fixing is sanctioned at the highest levels of the NYPD — said the Katakofsky allegations “casts an air of doubt over the entire investigation.”

Lynch noted that earlier this month, Deputy Inspector John McDermott, who oversaw the investigation, quietly filed retirement papers after 27 years with the NYPD.

“First, we see the highest ranking supervisor who oversaw the so called ‘ticket-fixing’ investigation retire suddenly and without warning,” Lynch said. “And now the veracity of the work by the principal detective is being called into doubt by the department.”

READ MORE: NY POST