FBI agents who investigated last year’s Boston Marathon bombing are defending their decision to release the suspects’ photos, even though they risked tipping them off.

In an interview that aired Sunday on CBS’s “60 Minutes,” FBI Executive Assistant Director Stephanie Douglas said investigators had to release images of the Tsarnaev brothers.

“Yes, I think at the end of the day, we really had no choice,” she said. “Believe me, the death of Sean Collier is not lost on the FBI. We consider it incredibly tragic event. But I think at the end of the day, given the facts as we knew them at the time, we made the best decision.”

Collier was the police officer at the Massachusetts Institute of Technology whom one of the brothers shot and killed three days after the bombing at the Boston Marathon, and the same day officials released the photos to the public.

Special Agent Rick Deslauriers said his wife actually cracked the case that night. On “60 Minutes,” he said his wife noticed breaking news that evening about Colliers’s death, and suspected it was linked to those responsible for the bombing.

“I did not believe that she had cracked the case at the time. I went to bed,” he said.

Deslauriers and Douglas woke up later that night to phone calls alerting them that one of the suspects was engaged in a shoot-out with police in the Boston suburb of Watertown. Officials eventually found the younger brother, Dzhokhar Tsarnaev, in a person’s boat in a backyard. The other brother, Tamerlan, died in the shoot-out.

During the younger Tsarnaev’s arraignment, Deslauriers said he was disgusted by the suspect’s facial expression.

“He had a smug grin on his face much of the time in the courtroom. He would glance over his right shoulder back to his relatives, and smile, and smirk at them. And I found that absolutely galling. And I found it reprehensible,” he said.

The bombing on April 15 last year left more than 260 people wounded and three dead.

Tsarnaev pleaded not guilty to 30 charges including using a weapon of mass destruction to kill people, and will face trial in November. The Justice Department announced earlier this year prosecutors would seek the death penalty in the case.

The new details of the case come as the anniversary of the tragedy approaches. This year’s marathon will be held on April 21.