Her boyfriend brought a loaded shotgun into their home. From what I can distill from the news reports, that pissed her off and — with alcohol involved — she blew a hole in the wall of their home. The pellets continued, damaging the siding of a neighbor’s home. From Oregon Live:

Police said Fleming was in a dispute with her 55-year-old boyfriend after discovering that he had brought his loaded 12 gauge shotgun into their shared home. They were discussing gun safety, including the proper handling of a loaded firearm.

It’s unclear the other details of the argument, but police said Fleming at one point intentionally opened fire from a close range from an upstairs room and blew out a hole about the size of a softball. The wall is comprised of sheetrock on the inside and a fiberboard exterior, according to a sheriff’s office release.

Apparently the discussion about gun safety and the proper handling of a loaded firearm left a few important points out.