For sure that needs to happen and no one should ever expect otherwise
another matter here
what about when the LEO doesn't identify himself during a raid in your home, and you gun him down before he does? Should you get charged with murder? or should it be self-defense?
2 different cases from Texas just this past year of Marvin Louis Guy and Henry Magee
http://thefreethoughtproject.com/prosecutor-seeking-death-penalty-officer-killed-knock-raid/