FBI reveals details on Boston bombing manhunt and video

Federal agents in charge of the Boston bombing task force talk for the first time about the moment they saw the suspects on video

Federal investigators of the Boston Marathon bombing tell the inside story of the manhunt a year after the infamous act of terror
Federal investigators of the Boston Marathon ... 00:54

Update: Scott Pelley's 60 Minutes report "Manhunt" aired on March 23, 2014.

Manhunt: Inside the Boston Marathon bombing i... 13:48
In an emotional recollection, the two FBI agents leading the search for the Boston Marathon bombing suspects tell Scott Pelley what they were thinking and looking for when they saw their suspects on video for the first time. Stephanie Douglas, executive assistant director of the FBI's National Security Division and Rick DesLauriers, the special agent who was in charge of the Boston FBI office, also reveal in gripping detail the exhaustive analysis of video which resulted in that identification in their first in-depth discussion of the manhunt. Their interview will be broadcast on 60 Minutes Sunday, March 23 at 7 p.m. ET/PT.

The key video is now part of the evidence in the prosecution's case and has still not been shown in public. It was from a business surveillance camera, which was scrutinized along with 13,000 other videos and 120,000 photographs taken near the bombing sites. Hundreds of agents combed through images around the clock until they successfully isolated Dzhokhar Tsarnaev, known as "white hat," in a dense crowd of spectators and then later, his older brother, Tamerlan Tsarnaev, wearing a black baseball cap.

What were they searching for? "Somebody who just doesn't look similar to others in the crowd who would be watching the race," DesLauriers tells Pelley. Then he recalls seeing Dzhokhar and the people in the crowd before the blast. "I see the subject, the individual who has been charged in the investigation. And I see people who are grievously, who are grievously injured in that blast. And I see individuals who died in that blast," he says. "Very, very emotional time when I look at that, to know what happened a few moments afterwards," says DesLauriers, who is now retired from the Bureau.

During the interview, Douglas and DesLauriers discuss a debate among law enforcement on whether to release the photographs of the two suspects. Some wanted to release the photos to seek the public's help in identifying them. Others contended it would force the suspects to flee. After hours of weighing the odds and being pushed in part by leaks and misinformation in the media, the decision was made to release the photographs. Both sides of the debate proved right. They did flee, but law enforcement now knew their names and were able to resolve the case.

During the suspects' attempt to escape, M.I.T. Police Officer Sean Collier was murdered, and a violent fire fight erupted with police in which the suspects were hurling bombs out the window of their car at police, officials say. A wounded Tamerlan Tsarnaev was killed when his younger brother Dzhokhar accidentally drove over him while he tried to get away. He vanished and a manhunt ensued throughout Boston and neighboring suburbs. He was later taken into custody. He has pleaded not guilty.

The FBI defends its position to release the photographs in light of the death of Officer Collier. "I think at the end of the day, we really had no choice," Douglas says. "Believe me the death of Sean Collier is not lost on the FBI. We consider it an incredibly tragic event. But...given the facts as we knew them at the time we made the best decision." DesLauriers agrees. "Nobody could have reasonably foreseen that a police officer would have been murdered." He tells Pelley, "What could have reasonably been foreseen is that these individuals could have had more bombs that they could have set off and caused carnage similar or even greater than what they caused on April 15th."

Pelley also interviews Boston U.S. Attorney Carmen Ortiz for the segment. Ortiz's office is prosecuting the death-penalty case against Dzhokhar.