And what indicators would those be? Because to those of us who aren't pursuing an agenda, it's looking pretty clear that the object of jealousy was Karen Reis, killed by the man she was in a previous relationship with after bringing a new man over to his home.
Are you that obtuse?
Employing Occam's Razor, the most rational explanation is that Reeves was the ex-boyfriend of Karen Reis, and that the recently-divorced Saturley whom the group just met was a guy who was trying to pick up Karen Reis.
The New Year's party moved back to the apartment and jealousy and alcohol made Reeves snap.