A man was killed in a field covered in snow. All that was left, was two parallel straight lines and a set of footprints in between. Who do the police need to look for?

not sure tough question

The police needs to find more trails as the parralel lines could of been some kind transporting item aka a wheel barrel (very random) and the foot prints should of been by the murderer as he walk on the snow carrying the "wheel barel" with the murdered man