charlie gone mysterious

Charlie could have done multiple things that the book did not say. He could have comitted suicide by doing a number of things. A clever idea would be that he buried himself in the ground like algernon was. But if he did commit suicide he probably did it because of algernon. And probably did it to be remembered with algernon. Or another idea is he dug up algernon and they both went some where where no one could find them. But if there is not a sequal to the story and no telling what happens at the end I dont want to guess what. I just like to leave a mystery a mystery.