Angelsboy is right
Even as a LEO I am going to be the best witness ever. Unless he goes mental. Here's why. When on duty I am prepared for an armed encounter. I have a uniform, vest, radio, extra ammo, handcuffs, etc... When off duty I don't have all those tools to my disposal. If the guy goes off the edge, it's just a bad day to be an off duty officer in that bank. You have to take action.
"Fast is Fine but accuracy is final.".....Wyatt Earp.