Can you answer this riddle....?

There where three boys Daniel, Mark, and Carl playig with rocks when one of them threw the rock into Mr. Bula's house. Before he could go outside and seewho did it they ran off. The only person who saw who dd it was his friend Martha. Martha wrote him a letter saying: ?, I think he did it. Whoever figures it out first, gets it right, and explains how you got itis the best answer!!