DETROIT -

A jury has found embattled Detroit contractor Bobby Ferguson not guilty on two of three firearm charges which originally were part of a bid-rigging case.

The jury was deadlocked on the third charge, leading the judge to declare a mistrial on it.

In an effort to streamline the trial, federal prosecutors dropped all charges against Ferguson except the firearm charges.

View court document: Counts against Ferguson dismissed

Ferguson already is serving a 21-year prison sentence for corruption committed while Kwame Kilpatrick was in office as Detroit mayor.

Ferguson's bid-rigging case involved allegations of fraud and illegal dumping at a housing project. His first trial in 2012 ended without a unanimous verdict -- a mistrial due to a deadlock.

Assistant U.S. Attorney Bruce Judge said dismissing some charges would save time for all parties, especially jurors.

Co-defendant Michael Woodhouse last week pleaded guilty to conspiracy.