UPDATE, 4:19 p.m. The Blue Line has resumed service through Maverick and Maverick Square has been re-opened to traffic.
Maverick Square is shut down as Transit and Boston Police investigate a double shooting inside the Blue Line station around 2:30 p.m.
One witness reports it happened on a train. WHDH reports two guys got into an argument on an inbound train, then one pulled out a gun and opened fire as the train was in the station.
Buses are running instead of the Blue Line between Bowdoin and Airport. Congress Street downtown was shut between State and Washington due to congestion caused by all the buses.