Except without that, the cops would have to know that Steven Avery was the last person she saw. If she had been seen by anyone anywhere after the visit to the Avery place their conspiracy would not work. Did they have access to that information before they planted the evidence to frame Steven? That would require…

I don't think anyone is suggesting LEOs killed the victim. But they opportunistically took a random murder and pinned it on Steven Avery, just as they took the sexual assault in the first case and pinned it on him. That involved planting the DNA on the key and a blood stain on the RAV-4, but that's not hard.

The line about hard boiled eggs and nuts is lifted from Laurel and Hardy's County Hospital.