What's odd about the way Jem's pants are mended?

When Jem, Scout and Dill were trying to escape the shotgun blasts comming from the Radley house, they went out through a fence, and Jem caught his pants on barbed wire and had to take them off so he could get free of the fence. The children made up a story so they wouldn't get in as much trouble. They said they had been playing strip poker with matches (matches were dangerous but cards were fatal), and Dill had won Jem's pants from him. Atticus instructed him to go to Dill's house and get his pants back, so to cover their lie, they had to get the pants back. Jem went around 2am to retrieve them, and when he returned, he said nothing, and kept moody and silent for a week, until Scout finally couldn't take it anyone and asked him what happened. Je said his pants were all ripped and in a tangle when he left them, but when he went back to retrieve them, they were folded across the fence and mended, but not like a Lady had sewn them, like something Jem would try to do, all crooked and uneven. It was like someone knew he would be comming back for them, ike someone had read his mind and knew what he was going to do. When they walked home from school that day when Jem finally told Scout what happened, they found a grey ball of twine, just like what had been used on Jem's pants, in the knothole in the Radley's tree, and they left it there for 3 days before they finally took it and added it to the other things in Jem's trunk.