Chris Brown's lawyers are asking a judge to dismiss the misdemeanour assault charge he is facing in Washington.
The singer's legal team filed a motion saying prosecutors misused the grand jury process to prepare for trial. Prosecutors have not yet responded to the motion.
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.