Attorneys for the next Baltimore police officer scheduled to be tried in the arrest and death of Freddie Gray are asking a judge to throw out an assault charge, saying prosecutors haven't outlined actions that constitute the crime.

Attorneys for Officer Edward Nero have also asked Judge Barry Williams in motions filed this week to bar prosecutors from using some evidence, including citizen video of the arrest and the knife found on Gray. They also want to keep prosecutors from mentioning an alleged lack of probable cause for the arrest.

Gray died after suffering a spinal injury in police custody. All six officers charged in the case have pleaded not guilty.

Nero is charged with second-degree assault, misconduct in office and reckless endangerment. His trial is scheduled for Feb. 22.