Brown's lawyers filed a motion Wednesday saying prosecutors misused the grand jury process to prepare for trial.
TMZ also claim that Brown's lawyers want the charges thrown out because prosecuters 'unlawfully got a sneak peek of witnesses'.
Report: TMZ claim that Chris Brown's lawyer -
Mark Geragos pictured above - want charges thrown out because
prosecutors 'unlawfully got a sneak peek of witnesses'
The site reports that lawyer Mark Geragos feels prosecutors didn't have the right to take the case before the gran jury.
Geragos claims the U.S. Attorney had already decided to reduce the charge from a felony to a misdemeanor assault.
Prosecutors have not yet responded to the motion.
In the dock: Chris Brown as he appeared in court
with his attorney Mark Geragos for a probation violation hearing during
which his probation was revoked by a Los Angeles Superior judge earlier
this month
Brown and his bodyguard were arrested in Washington in October. Both are accused of punching a man.
At the time Brown was arrested, the Grammy winner was on probation in California for a 2009 attack on singer Rihanna, his then-girlfriend.
After his arrest in Washington, a California judge ordered Brown to receive anger management and other treatment.
That judge jailed Brown earlier this month after he was dismissed from the treatment facility.
Prosecutors want Brown brought to Washington for his trial, which is currently scheduled for mid-April.
History: At the time Brown was arrested, the
Grammy winner was on probation in California for a 2009 attack on singer
Rihanna, his then-girlfriend