She’s dead, he killed her. Now for the burden of proof.
Maybe he can use the “she died on her own and I was just disposing of the body” defense that the homemade submarine guy (Peter Madsen) used.
The AP just picked the story:
I’m guessing the feds will assist at some point if they’ve not already done so. They can, and will, check phones, locations, time stamps, tower transmissions, etc. They’ll look at surveillance cams, license plates, and probably a whole bunch of stuff the perp hasn’t remotely considered.
But there’s a missing person’s report and he’s likely to be the last person to have seen her. They can’t detain him, but you can bet your ass that state and federal resources are going to be used to determine her whereabouts, with a watchful eye on him. The family of the presumed victim can also hire a private detective.
Under the assumption that he knows her whereabouts / fate but has decided to stay silent, what progress can be made by watching him? What might a private detective be able to accomplish?
They’re not going to leave him alone. He can refuse to cooperate, but that won’t stop the investigation.
They could monitor him to see if he goes back to dispose of the body, or if he enlists someone’s help to do that remotely on his behalf.
Edit to add: and if they get a warrant, they can wiretap his phone lines in the event he blows his cover to a friend, although if he is using an encrypted end-to-end program like Signal, they might be shit outta luck.
There’s more information here:
Hard to imagine a sane person doing either of these.
Or this.
Between living online, remote control vehicles, self-driving cars, and covid restrictions, I read the words “virtual vanning” and I thought … maybe?
I won’t pretend to understand what young people are doing nowadays.
That is strange. 
especially when young.
The first thing they’re likely to look at is the couple’s data. They can open up social media & email accounts. They can look at Google searches. They’ll look at financial activity. If he was smart enough to cover all his tracks, that will make their investigation harder but not impossible. They’ll also try to pinpoint the last known location. He was smart to lawyer up, but that will only make law enforcement more determined to investigate him as a prime suspect in a case of suspected foul play using whatever legal means they have at their disposal.
Chances are good that this guy slipped up somewhere along the way.
Like everyone else, I expect that it will turn out that he murdered her. Despite this, I hope that the police don’t get so fixated that they ignore other possibilities because people is weird and sometimes we’re wrong.
Bodycam video (note it’s an hour and 17 minutes long):
Chances are at least good the van can be traced to a place fairly close to where he and she parted ways. Vans need gas & people need food; lots of video surveillance of parking lots & roads. Motorists who might have been in areas of interest can be asked to check dashcam video. It’s probably hard to enter a park or campground without leaving some sort of evidence.
It’s been a while though. He was home on September 1, while her parents didn’t start asking about her until ten days later or so. So any useful surveillance is at least two weeks ago. How long are these recordings stored?
A Tip of the hat to the Moab police. They put a lot of time into this stop. Separating them for the night makes sense.
Brian didn’t seem inclined to strike back. But, that may have changed the next time they fought.
Corporate convenience stores upload video to the cloud and keep it forever. Independent stores have standalone loop recording systems that may only have the last week. Dashcams may just have the last 8 hours of video. The authorities will likely use credit card and phone data to identify the stores to visit to see if they have usable video.