Certainly not strict liability, and it's apparent there was no intent. However, without checking local laws, seems like
there is some culpability. Otherwise, anyone can claim ignorance when they kill someone (i.e., someone else told me it wasn't loaded, shooting blanks, etc.). Just seems like there has to be some liability, but certainly not 1st degree murder. Some form of manslaughter, etc. Highly dependent on local laws, which I know nothing about.