I agree. IMO, the perp has a history of violent behaviors and giving a confession would mean giving up control. However, I am hopeful that all of those surrounding him/her are providing enough details for LE to build a strong enough case.
To me the longer the search goes the less likely someone is going to confess, I think it emboldens the perp. I do think LE knows what happened and they are connecting the dots and I do think they have "stuff".