Complex sentence: Though they initially interact well, Starr senses Astrid is having an affair with her live-in boyfriend and after a loud argument with him, she runs into Astrid's room in a blind rage and shoots her.
Split into simpler sentences: Though they initially interact well, Starr suspects Astrid having an affair with her live-in boyfriend. After a loud argument with him, she runs into Astrid's room in a blind rage and shoots her.