(Spoilers Published) Bran Murder Case

The usage of valyrian steel blade is kinda perplexing because of the value of the valyrian steel. It can be done by even with a bronze blade. One thing comes to mind that the relationship between The Others and valyrian steel and the theories that suggests there is a link between Starks and The Others. Bran may get killed with a regular blade but maybe valyrian steel is the only way to truly kill a shapechanger/greenseer.

Most common explanations suggests valyrian steel blade with Littlefinger who wants the murder case track down to Tyrion and start a Lannister-Stark war. Which makes sense. Though consider you are the murderer and you are in possesion of a super expensive blade that you can sell at say Braavos and live the rest of your life as a rich happy man. What would you do? Evading Littlefinger's wrath can be difficult but killing the Warden of the North's boy and geting out of the north would be also very difficult. You have no guarantee that The Littlefinger dispose you afterwards.

I suspect that the murderer may have strong motivations other than money to kill Bran. The Littlefinger still be involved with this but who knows what Littlefinger is up to or who he aligned with.