Black Livers Matter. Thugs with guns don't. 

Soooooooo - more practical theory, cops ran his plates when they saw something suspicious so the cops KNEW who this guy was and his record as they were approaching the vehicle. It is standard practice for LEO to run plates before they approach the vehicle for obvious safety reasons. 

Hmmmmm - the wife obviously knew he had a gun because she tried saying he didn't have a gun but in the same breath kept saying "Keith don't you do it".  I wondered why she kept using those words because "don't you do it" implies she knew exactly what her husband of 20 years was going to do. She would know, wouldn't she. 

Conclusion: Justified shooting of a career criminal. Case closed.