It reminds me of this old French film "La mariée était en noir" (="The Bride wore black"), 1968.
Crime scene begins at 1:50. A group of drunken friends are playing with empty guns, one of them loads one of the guns, another one takes the gun believing it's not loaded, and kills a man at his wedding in front of the church.
The men escape, but the bride spends the whole film looking for them and she kills them one by one.