Riddle of Sherlock Holmes and the broken window

You’ll really have to use your brain with this Sherlock Holmes riddle.

One snowy night, Sherlock Holmes was at home sitting by the fire. All of a sudden a snowball came crashing through his window.
Holmes got up and looked out the window just in time to see three neighborhood kids who were brothers run around a corner. Their names were John Crimson, Mark Crimson and Paul Crimson.
The next day Holmes got a note on his door that read
“? Crimson. He broke your window.”
Which of the three Crimson brothers should Sherlock Holmes question about the incident?