There are always exceptions of course, but statistically, in this sort of crime scene, at least one of the victims knows exactly who's killing them and why they're killing them.
All of that is true. But the article doesn't mention religion, thus my skepticism.
Somebody is Pissed off. Maybe it's the former tenant.
WNBC-TV in New York reported authorities were investigating whether a former tenant who had had a dispute with the family was involved.