Police say the truck was a white Freightliner daycab tractor with “Ryder” written on both doors.
That would be a rental then? As in "Ryder Rents Trucks?" Might they have GPS locators? If so, it should be possible to find out which one made off with the trailer.
My thinking was they could use their tracker info to find out which of their rental tractors were in the area at the time of the theft. Then trace that back to the renter.