Many residents woke to find a second murder suspect dead , manhunt under way . Subway , taxis , MIT , Amtrak , local buses shut down as police conducted manhunt . An MIT police officer was killed , and a transit police officer was injured during the incident . Police officer was seriously injured and transported to the hospital , '' Boston police said in a release . Cambridge and Watertown are hot spots in investigation as police pursue second suspect .
Many residents woke to find a second murder suspect dead , manhunt under way . Subway , taxis , MIT , Amtrak , local buses shut down as police conducted manhunt . An MIT police officer was killed , and a transit police officer was injured during the incident . Cambridge and Watertown are hot spots in investigation as police pursue second suspect .