The request was filed Monday in U.S. District Court in Detroit.
Sentencing for Kilpatrick and Ferguson is this week in the corruption case, and federal Judge Nancy Edmunds is expected to determine the restitution amount.
Kilpatrick's lawyer on Friday asked Edmunds for a prison sentence of no more than 15 years, about half the punishment sought by prosecutors. The U.S. Attorney's Office recommended at least 28 years.
In March, Kilpatrick was convicted of racketeering conspiracy, fraud and tax offenses. The government says he took bribes from Detroit contractors and ensured that Ferguson got millions of dollars in work from the city. Kilpatrick quit office in 2008.
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