I don’t think this case is remotely close to becoming “cold.” The intensity of the latest search, indicates as much.
Cases aren’t always made very quickly, especially one like this. This almost certainly occurred in broad daylight, and there are going to be no shortage of roads to go down.
Witnesses, forensics, video, cell phone data, GPS; God knows what else. Just because we don’t see certain things, doesn’t mean they aren’t happening.
Gannon’s body is likely the missing link (in regards to an arrest), and it could take some time to find him. I strongly believe they will though.
It’s been 3 weeks. Early days.