Prosecutors in Lille, France, said earlier in May investigators submitted new evidence based on testimony from two Belgian prostitutes that could implicate Strauss-Kahn and two other men in an alleged gang rape in December 2010, Radio France Internationale reported Monday.
Strauss-Kahn, two businessmen and a police chief already are charged with "aggravated pimping in an organized gang" in Lille for allegedly orchestrating a prostitution ring for sex parties in France, the United States and elsewhere.
Testimony from one of the prostitutes indicated she was forced to have non-consensual sex while in Washington in December 2010 with Strauss-Kahn and others but did not file a complaint, RFI said.
Strauss-Kahn's lawyers have denied the accusations, saying their client "absolutely contests having committed the slightest act of violence of any nature whatsoever."
Strauss-Kahn was considered a front-runner for the French president until his arrest last year on accusations he sexually assaulted a New York hotel maid. The New York charges eventually were dropped but Strauss-Kahn, 63, since has faced several criminal and civil actions linked to alleged sex crimes.