Anytime a lawyer asks the judge to do something it is called a "motion" ("Your Honor I move that..."). If your rights have been violated by the police or the District Attorney's office, this is where you can seek justice.
What kinds of pre-trial motions are there?
• Suppression Motions
By far the most common pre-trial motion is the suppression motion. If evidence has been gathered illegally an attorney may make a motion asking the judge to prevent the District Attorney from using that evidence at trial. Similarly, if a confession or other statement is improperly taken by the police, an attorney may ask the judge to prevent the statement from being used at trial. In rare cases (Marital privilege, 5th & 6th Amendment cases) an attorney may be able to prevent a witness from testifying altogether.
• Motions to Compel
The District Attorney's office has a legal duty to turn over all evidence they obtain so that the defendant can properly prepare for trial and make educated choices about plea-bargains. Unfortunately District Attorneys fail to do this at an alarming rate. Defense attorneys are often forced, therefore, to make motions to compel. As the name suggests, a motion to compel asks the judge to compel (force) the District Attorney to do their job properly. An offshoot of the motion to compel is the Pitchess Motion. If your case involves issues of police brutality or excessive force, an attorney may make a motion to compel the police agency to turn over copies of prior complaints against the officers, so that these may be used to establish the officers' violent character at trial.
• 995 Motion
In certain felony cases an attorney can bring a motion to dismiss if the defendant was wrongfully sent to trial after the D.A. presented insufficient evidence at the preliminary hearing. Called a 995 motion, this motion serves as a type of Preliminary Hearing Appeal in rare cases where the preliminary judge makes rulings that are simply unreasonable.
• Trombetta Motion
In the rare case that police or prosecutors destroy evidence pointing towards a defendants guilt, a motion to dismiss for unfair trial tactics (called a "due process violation" in legal terms) can be made.
• Severance Motion
Often times the District Attorneys office will ask that a defendant unfairly stand trial with "co-defendants" who have committed more serious crimes, or who have much stronger evidence stacked against them. In such a case an attorney may ask the judge to "serve" (cut off) the defendant from the main case so that they can be tried separately.