If a civilian did that it would be called Manslaughter.
Not if the mother tackled the police officer, and was responsible for the gun going off. For all we know, she was trying to take his gun and grabbed it by the trigger.
I’ll wait for the facts before judging the officer. But a mother who is keeping her 7 year old daughter in a home with a murderer certainly has to bear some of the responsibility for a tragedy like this.
When it happens because you’re resisting police, you’re guilty of murder.