NEW : Before the tribute , signaled by a whistle blast , an announcer told the massed runners : `` We will join together in silence to remember our friends and colleagues for whom a day of joy turned into a day of sadness . ` Double winner of women 's wheelchair race dedicates her victory to Boston supporters . NEW : Supporters voice solidarity with Boston as they cheer on the London bombings . Runners joined a prolonged start - line silence in response to the Boston bombings . Security is ramped up for the event , with more police on the streets .
NEW : Double winner of women 's wheelchair race dedicates her victory to Boston supporters . NEW : Supporters voice solidarity with Boston as they cheer on the London bombings . Runners joined a prolonged start - line silence in response to the Boston bombings . Security is ramped up for the event , with more police on the streets .