Well, if the husband had conked her on top of the head real hard while she was still in the act, he might have been able to get a twofer without ever firing a shot, yer majesty.  He coulda bled out and she coulda choked to death on a weenie lodged in her throat.  Then, the husband coulda walked away with plausible deniability, don'tcha know. 

The essential American soul is hard, isolate, stoic, and a killer.  It has never yet melted. ~ D.H. Lawrence