That's what I think too. Why would Jeff be so "curious" about what they were doing behind the store? Why would he care, unless it was jealousy? I think Jeff knew why Carter and Natalie were off alone, but he just had to see it for himself. He wasn't actually innocently curious, but trying to verify his suspicions that Carter and Natalie were together. Then flew off the handle once he figured it out. I still can't rectify that with how Jeff appeared to be with Kelsie - over the top lovey dovey. Maybe something happened with her that weekend - their relationship seemed volatile from his Instagram postings. Or he felt abandoned by being kicked out of his grandparents', and took it out on the first happy people he saw.
I also wanted to respond to something in the old thread, but it's not letting me quote the OP's. I don't believe that Detective Bennett's emotional response was from witnessing a tape of the murder. She broke down right at the moment the mom broke down, during a terrible description of the act, so it was probably just a contagious emotional response. Bennett also saw the autopsy, so she knows the horror of what was done to them without seeing a video.
But with that being said, I'm not convinced that the murder was
not caught on video. From the
sky photo of the store, with the yellow dashed line box, it looks like the cars are parked directly left of the
small dumpster, to the left of the cage, back door and camera. What is in dispute is if the camera was recording or in view of the murders. If they were parked next to the small dumpster, it seems like the camera could have caught it. I know the detective
says it's not on camera, I'm just trying to understand why it's not, given the proximity to that camera.