Union activists have a word of advice for the Justice Department’s Criminal Division chief Mythili Raman.

If big banks are guilty of LIBOR manipulation, they should be forced to admit wrongdoing.

And so far, the have sent Raman more than 2,000 postcards making the point.

“If investigators find that more big banks are guilty of LIBOR manipulation, they should not be let off the hook without admitting wrongdoing,” the back of the postcard implores. “We demand that there be no new LIBOR settlements without an admission of guilt. Too big to fail banks like Deutsche Bank, which profited immensely from huge bets on LIBOR changes — while accepting billions in emergency Fed funding — should not be above the law. If they manipulated rates, they should admit it. No free passes!”

The front of the postcard reads: “Big banks made big bucks on LIBOR trades. Deutsche Bank alone made $654 million on LIBOR based trades in 2008, while accepting billions in emergency funding from the Federal Reserve. Enough is enough.”

The activists are concerned about a pattern of deferred and non prosecution agreements being dished out to major banks and other corporations.

Raman will be the keynote speaker at a conference May 3 at the National Press Club titled Neither Admit Nor Deny: Corporate Crime in the Age of Deferred Prosecutions,  Consent Decrees, Whistleblowers & Monitors.

In June 2012, Barclays was granted a non prosecution agreement despite its misconduct in the LIBOR scandal.

The postcard campaign is part of the Deutsche Bank Risk Alert, a project of the Unite Here union — the international union for 250,000 hotel, gaming, and food service workers in North America.

Marty Leary, deputy director of research at Unite Here, said that the union is in negotiation on behalf of 2,400 workers at the Cosmopolitan Casino in Las Vegas, which is owned by Deutsche Bank.

Unite Here is also seeking to unionize another Deutsche Bank company in Las Vegas, the non-union Station Casinos.