TODAY | April 20, 2013
>> morning. one boston bombing suspect, the surviving suspect in custody seriously wounded. his brother, the other suspect, is dead.
>> authorities were able to track them down after they shot and down and killed a true hero. a campus police officer at m.i.t. named sean collier. ron allen has more on them. ron, good morning.
>> reporter: good morning, erica. this is an absolutely heartbreaking story. one of the four people who died as a result of this incredible week of violence, sean collier was just 26 years old. a campus police officer for the massachusetts institute of technology or m.i.t. as everyone knows it. he was nearing the end of his shift when he was ambushed by the two brothers shot multiple times in his police cruiser . he died there at the scene. at first this incident was not ken connected to the bombings at the marathon. once calls went over the police radio , police started putting one and one together and adding it up. a chase ensued for the suspects. the next thing that happens along the way when there's a shootout is there's another police officer who is wounded. richard donahue who is 33. he was a transit officer for the transit authority , buses and subways here in boston. he's now fighting for his life at a hospital. he was gravely wounded. he's a father with a young child who is just about 6 months old or so. now another interesting part of this story is that the two men collier and donahue know each other. they were very close friends according to their colleagues. they attended the same police academy together about three years ago and graduated together. so just a horrific series of events there. collier is dead. donahue fighting for his life as this all just played out in a horrific way. erica?
>> all right. ron allen , thank