Actually this story does not portray all details involved in this incident and maybe you would understand why they seized it if you knew (seizing it for tests is for the benefit of the clerk). My agency was also involved in this investigation (four or five NOVA agencies were involved in this for reasons I won't go into). The shooting appears to be self defense and I cannot be more happy for the outcome (good guy alive, bad guy shot).
Of course they will seize the weapon, it's still being investigated and it's evidence. Police can seize evidence from innocent people if has impact on a case. In fact, charges will be filed against both bad guys so there was a crime involved. I hope the clerk has another gun and agree he did everything correctly (from what I know). Most likely the Commonwealth Attorney will still submit this case to a grand jury to back a decision not to charge.
SouthernBoy-You really think you can shoot someone in self defense and police can determine that on scene and let you walk away with your weapon? Fantasy world. I would not even want that if I was involved in a self defense shooting. I would want police to do a thorough job investigating. In fact, the police will throw the investigation to the C.A.'s office to determine it truly meets the definition of self defense. A vehicle accident is much different than a shooting. If you accidentally hit and seriously injure/kill someone who ran out in front of you, then you are not guilty of a crime, and yes, your car will be impounded until the investigation is over (sorry to tell ya). A thorough investigation takes some time and it will take some time for the legal process to determine it was self defense and not to take it to trial.
Maybe someone can lend him one of their guns?