(WXYZ) - Former city contractor Bobby Ferguson is asking a federal judge to set aside his conviction on racketeering and bribery charges.
It's a standard step that defense lawyers take before a formal appeal is filed in a case.
Ferguson lawyers Gerald Evelyn, Susan Van Dusen, and Mike Rataj filed the motion on Friday. They argue that federal prosecutors failed to prove their case, and ask the judge to grant Ferguson a new trial if she doesn't set aside the guilty verdicts.
Former city contractor Bobby Ferguson is asking a federal judge to set aside his conviction on racketeering and bribery charges.
A jury convicted Ferguson and his long-time friend, former Detroit Mayor Kwame Kilpatrick on several crimes back in March.
Kilpatrick's father, Bernard, was convicted on a tax charge.
Ferguson's attorneys say federal prosecutors failed to prove that he gave Kilpatrick the cash that was a focus in the case.. and they suggest the jury reached its verdict based on "pure speculation."
If the judge won't go for that – Ferguson's lawyers want a new trial.
The say the court allowed the case agents from the FBI and EPA to improperly interpret text messages and recorded phone calls during the trial.
They also say the judge should not have allowed 5 key witnesses to testify about out-of-court conversations.
Ferguson's lawyers argue, as well, that the judge should have declared a mistrial after federal prosecutors called on the jury during closing arguments to convict the members of the Kilpatrick Enterprise as a civic duty.
The government has until June 7, 2013 to respond to the motion for a new trial.
Lawyers for former Detroit mayor Kwame Kilpatrick are expected to file similar motion.