What's the Point of a Hollow Point Bullet?

The family has a theory at least about the order of things I'll be interested to hear what you think. What they surmise is that the killer came in and caught Niels and his steps on Billy Offguard back in the kitchen. They're cornered. Billy has time to pull out this jackknife out of his pocket to try to defend himself. And Billy and Niels are killed first and then in the ruckus, just feet away from her bedroom, Daisy comes out, is potentially shot in the arm. She staggers back onto the bed, which is where she's found. No sign of sexual assault or anything like that. So do you think that that sounds