when lauryn ricketts . >>> new enhanced video will be shown to the grand jury in the killing of a 12- boy. rice was carrying a pellet gun when he was shot. attorneys for the boy's family want their own experts to testify. the defense argues that the officer had no way of knowing that rice was carrying a pellet gun. >>> from chicago to minneapolis, baltimore to ferguson and cities all over the country, the use of police force is under more scrutiny than ever. >> it certainly is. "news4' "news4's" aaron gilchrist went in sierra. of answers as to when officers use force. >> reporter: it's a training scenario officers use every year, making the call and firing on a suspect. in prince george's county officers are taught to consider several other steps before a bullet ever leaves the chamber. >> to be able to use force to protect citizens, protect themselves, and force laws, things like that. they have to have a clear understanding. there's a lot riding on it. >> reporter: he runs the specialized training unit, the use of force team. he says training starts with dozens of hours in the class