Easy! Nobody is a crazy idiot who was shot when he was carrying that stuff. He dropped them afterwards. The reason the "but" is in the sentence is because the reader would assume that the crazy person, who was unfortunate enough to be named "Nobody", was also carrying a knife, which he thew at the owner of the lawn. After he was declared dead on the scene and removed from the lawn the objects were not picked up yet until the officers returned to the scene to pick them up as evidence... the knife, which ended up in the middle of the road, was also picked up as evidence. These items were not "put"/placed anywhere. They were dropped accidentally.
If I see another snowman, I will tell them that they were put on the lawn. They merely changed their elevation when the snow melted.