Kevin Donovan, a Somerville resident who was a spectator Monday, heard what sounded like cannon fire. Walking over to the course, Donovan saw police officers run into the middle of the road holding their hands up to stop runners from proceeding. Runners asked spectators what was going on."
"They're freezing out there," said Donovan. "People were giving them coats."
Donovan said the stalled runners began to combine with the crowds walking back from Kenmore Square following the Red Sox game.