Maybe that was the ruse for entry? Not at all claiming xbf knew culprit. But if one, or all, of the tenants were stalked...their associations were likely known-OF by the culprit.
That possible theory explains the persistence of calls and the 'no signs of forced entry [implying the resident must've known culprit].' That statement and logic drives me bonkers.
That can be rebutted with how victims were found in their beds. Okay, maybe. Buuuut....
1) I don't come from a world of bucolic bliss where people don't lock doors. No. Just no. So, admittedly, I do project that onto the cases I read about. Sorry, my bad.
2) Say somebody's watching the house and sees the girls return. Culprit approaches the door, knocks, and is persistent about getting in touch with xbf; gives the ruse 'I gotta get in touch with xbf, blah blah blah, wordsalad.' Not saying xbf knew this person, but likely culprit knew OF xbf.
3) Girls realize this urgency from culprit and he's loud/disruptive while other tenants are sleeping - girls don't appreciate that but still want to respect other tenants' peace. To appease culprit girls are like 'all right, let's go upstairs and hang out in our room while we wait for a return phone call or text.'
4) That return contact doesn't happen and bam - attack happens. Attack likely would've happened regardless of returned call/text, imo.
Again, not saying xbf knew anything of or about this culprit. But, culprit likely knew OF the tenants associations. At first, I thought calls were about dog (and pup off-site, leaving owners worried especially with word of other pup's demise) or girls being girls while intoxicated. But, now I'm kind of thinking Murphy was on site, for some reason.
So, now with everything known and released thus far. I think that was the ruse for entry and gives way to 'no signs of forced entry.'
Purely my own speculation and opinions and willing to be totally wrong.