WASHINGTON—Families of victims of the two 737 MAX crashes on Thursday said the U.S. Justice Department violated their rights when it struck a deferred prosecution agreement with Boeing in January. Relatives filed a motion arguing the United States Government “lied and violated their rights through a secret process.” They have asked a U.S. judge to declare that the order violated victims’ families rights to rescind Boeing’s immunity from criminal prosecution that was part of a $2.5 billion agreement. The Justice Department did not immediately comment. Boeing declined to comment. The settlement allowed Boeing to avoid prosecution, includes a fine of $243.6 million, compensation to airlines of $1.77 billion and a $500 million crash-victim fund over fraud conspiracy charges related to the plane’s flawed design. The deferred prosecution agreement is a form of corporate plea bargain. The Justice Department “chose to deliberately conceal its investigation and covertly negotiate with Boeing about …