NY 1 has the story of the lawsuit by the heirs of George Grosz against MoMA for the return of three works bought by the museum in the 1940s and 50s.

ArtInfo.com has a quote from Marty Grosz:

The heirs also claim that they tried to negotiate with the museum but that the negotiations broke down and the museum refused attempts at mediation, which led to the suit, filed on April 10 in federal court in New York.

“We are very respectful of the MoMA, one of the leading modern art museums in the world. Unfortunately they were not willing to apply the principles of the Washington Conference and reach a ‘fair and just solution’ in this case,” said Marty Grosz.

George Grosz Heirs Sue MoMA (ArtInfo.com)