One curious thing after reading the probable cause affidavit about the cell phone pings on the morning of the murder and the next day -- its striking that the areas the phone traveled outside of Moscow and Pullman were near the sites of the Lewis Clark Valley Serial Killer murders. Obviously, our suspect here is way too young to have been involved in those murders, but it was like a tour of the areas. Not to mention, Lewiston is near the Snake River and Columbia River, a great place to get rid of a murder weapon. One of the victims in those murders, Kristina David, was traveling by bike between Moscow and Lewiston, south on 95, where the cell phone pinged in this case, when she was abducted. Small world.
If you have not caught up on the Lewis Clark Valley murders, there is a great documentary out there on it and here's the wikipedia page. An interesting twist in that case is that LE very much thinks they know who committed those crimes back between 1979 and 1982, but have not been able to prove it (again, those crimes were nowhere near as brazen as these).
en.wikipedia.org