The NYPD is trying to teach cops to tell the truth – and nothing but the truth – when they’re in court.

After a spate of cases in which cops were prosecuted for lying, the Police Department has created a handbook with tips for testifying.

At least one of them seems elementary: “Do not concoct answers or explanations – just state that you do not know.”

The tips are part of a mock trial workshop designed to teach cops how to succeed on the stand without distorting the truth.

“The message is that the job doesn’t stop at arrest,” said Timothy Koller, executive assistant district attorney for Staten Island DA Daniel Donovan.

Police Commissioner Raymond Kelly’s special counsel for legal issues, Katherine Ann Lemire, convinced city prosecutors to join the effort, sources said.

The DAs provided staff to act as prosecutors and defense lawyers and grill the cops in mock trials, teaching them to avoid “testilying.”

“If someone is dishonest and is just going to lie, this isn’t going to stop them,” said one assistant district attorney who has worked with the cops.

“But for the guy who makes a lot of arrests, it is a chance to see how his work on the street translates, or doesn’t, in the courtroom,” the prosecutor said.

Among the helpful hints:

– “Concede your errors in paperwork and prior statements.”

– “Remain alert – do not allow the defense attorney to lead you into inconsistent statements.”

– “Greet the jury with a smile upon entering and exiting the courtroom.”

Cops are also told to avoid frequent answers of “I do not recall,” long pauses after questions and looking for help from the prosecutor.

They’re told to avoid jargon, focus on the jury during cross-examination, and refer to victims and witnesses – but not the defendant – by name.

The role-playing – a pilot program to be expanded this year – puts cops on the stand to testify about a fictional gun or drug arrest.

It aims to avoid disasters like the 2009 perjury conviction against a Bronx detective who testified he never questioned a gun suspect – when the suspect had taped the conversation.

A Bronx police officer was convicted the same year for inventing a story about spotting a burglary suspect in a building basement he’d never entered.

“There were instances when officers, with nothing to gain personally, jeopardized themselves on the stand,” said Deputy Police Commissioner Paul Browne.

“Commissioner Kelly wanted to make sure that doesn’t happen and that officers let the chips fall where they may.”

(Source: NY Daily News)