(CBS News) The successful manhunt for the Boston bombing suspects came with a heavy toll. An MIT campus police officer, Sean Collier, was executed in cold blood, and a Boston transit officer, Dick Donohue, was critically wounded. The two officers, CBS News has learned, were friends.
If not for these two officers and their colleagues, the drama that unfolded Friday may have had a very different ending.
Following Friday's shootout with Tamerlan and Dzhokhar Tsarnaev, and the manhunt and residential lockdown that followed, Watertown Police Department Police Chief Edward Deveau said, "I've been in law enforcement for 30 years, and I can't be prouder of my profession than I have been in the last 48 hours."
The showdown between law enforcement and the suspected marathon bombers may have saved many lives, but it came at a cost. Pat Kelleher, Collier's aunt, said, "We're all devastated by the loss of Sean."
President Barack Obama said of Collier, "He died bravely in the line of duty, doing what he committed his life to doing."
Police say 26-year-old Collier died in an ambush at the hands of Dzhokhar Tsarnaev, 19, and his older brother Tamerlan, 26, as they ran from the law. Hours later, officials say the brothers got into a fierce gun battle with police officers. Tamerlan Tsarnaev died in the shootout, but not before Boston transit officer Donohue took a bullet to the leg, severing his femoral artery.
Chief Paul MacMillan, of the MBTA Transit Police Department, said, "He engaged the terrorists in the most difficult situations that none of us begin to imagine."
Dr. Russell Nauta said of Donohue, "The officer's blood volume was almost entirely lost. To the point of the heart stopping."
CBS News is told Donohue and Collier were friends from police academy. Now, one is dead, and the other is fighting for his life. But both are being called heroes.
Donahue's brother, Ed Donohue, said, "With complete disregard to their own safety, officers withstood a barrage of gunfire and explosives more reminiscent of a warzone than a quiet suburban street."
Donohue remains in critical condition, but doctors say they're optimistic he can recover. To those responsible for last week's violence, his brother had this message: "We will persevere and we will fight because we know no other way to live, but free. Thank you very much."
Officer Donohue remains sedated, but was apparently able to squeeze his wife's hand.
In the meantime, his family is asking people to pray for Collier and the three people killed at the marathon.
Watch Elaine Quijano's full report in the video above.