The motion came a day after lawyers for former Detroit Mayor Kwame Kilpatrick also asked U.S. Chief District Judge Gerald Rosen to dismiss the case, arguing no evidence had come forth, after dozens of depositions, to suggest Kilpatrick obstructed the investigation into the killing of Tamara Greene, who danced under the name "Strawberry."
Rosen ordered Detroit to publicly file the motion after the city inadvertently filed and quickly retracted a near-final version that should have been filed under seal.
Greene, 27, was killed in a drive-by shooting April 30, 2003, some six months after she allegedly danced at a never-proven party at the mayor's official residence, where she was also allegedly was assaulted by the mayor's wife, Carlita.
Greene's family sued the city and Kilpatrick, alleging they sabotaged Greene's murder investigation to keep her killers from being brought to justice.
Greene family attorney Norman Yatooma had no immediate comment on the latest filing. He has three weeks to respond to it.
Kilpatrick resigned Sept. 18, 2008, after pleading guilty to obstruction of justice in an unrelated matter. He is in state prison for violating his probation in that case and was indicted June 23 on tax and fraud charges in federal court.
The trial on the latest charges is scheduled to begin in November.