It didn't happen in Boston. If you think it did, you need to inform yourself of what constitutes martial law.
I've seen several people on this forum talk about martial law being imposed on the Boston area. I don't know where this idea came from, possibly from the heavy police presence and the fact police agencies were conducting some door-to-door searches. Or maybe some folks spend a little too much time tuned in to Alex Jones.
Google it if you don't know what it means.