Thirteen problems

I read the next short story and it was my favorite one so far (I've read three). It was cold Ingots of Gold. It was about a ship that sank and its bullion was missing (the place where you keep the gold). The police was investigating the case. One night there was a storm and Mr Newman left to go on a walk and went missing. He was found in a ditch on the next day. His story was that he saw some man carrying something out of this ship and transporting it to a cave. He followed them, but they took him in a lorry and left him where he had been then. The tyre tracks matched to a lorry owned by Mr Kelvin, but his maid confirmed that it hadn't been used. In the end, we find out it was Mr Newman who planned it all in order to hide that he stole the gold. He had taken out a tyre of the lorry and had put it on his own and that's where the confusion was.