I don’t know if you have noticed what Bob said during the interview.
When Casey's case was reopened and the police searched the entire lakeside cottage and salvaged the lake, and wanted to find the body to file the case, the reporter asked him if he knew what the police were doing, and he replied that they wanted to find the body part. Normal people Speaking of "corpse", only body, not body part, but the original meaning of his sentence should be: I know they want to find the corpse to file a case. Find the body, ordinary people will say find the body. Body part is unless the premise is a dismembered body. Just like the beginning of the film.
So he killed Casey and dismembered her. So he knew that it was a body part and not a complete corpse, so he subconsciously said that they were looking for a part of the corpse. As for the dismemberment, I don't think he can move Casey? I remember his original saying that when he killed his neighbor, he was dismembered because he couldn't move the body. At the beginning, he wanted to dismember into two pieces. As for the dismemberment and multiple pieces later, I guess he was dismembered into two pieces and couldn't move it. So after analysis, she should not be able to move Casey.
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