The criminal complaint against surviving Boston Marathon bombing suspect Dzhokhar Tsanaev contains an affidavit from Special Agent Daniel R. Genck, with the Federal Bureau of Investigation. He is assigned to one of the Boston Field Office’s Counterterrorism Squads, and is a member of the Joint Terrorism Task Force. Genck’s affidavit discusses the contents of video evidence obtained by the federal government.

Genck states:

I have reviewed videotape footage taken from a security camera located on Boylston Street near the corner of Boylston and Gloucester Streets. At approximately 2:38 p.m. (based on the video’s duration and timing of the explosions) – i.e., approximately 11 minutes before the first explosion – two young men can be seen turning left (eastward) onto Boylston from Gloucester Street. Both men are carrying large knapsacks …

The affidavit grows more chilling as the time of the bombing approaches:

At approximately 2:45 p.m., Bomber Two can be seen detaching himself from the crowd and walking east on Boylston Street toward the Marathon finishing line … Approximately 15 seconds later, he can be seen stopping directly in front of the Forum Restaurant and standing near the metal barrier among numerous spectators, with his back to the camera, facing the runners. He then can be seen apparently slipping his knapsack onto the ground …. The Forum Restaurant video shows that Bomber Two remained in the same spot for approximately four minutes, occasionally looking at his cell phone and once appearing to take a picture with it.

The affidavit continues:

Approximately 30 seconds before the first explosion, he lifts his phone to his ear as if he is speaking on his cell phone, and keeps it there for approximately 18 seconds. A few seconds after he finishes the call, the large crowd of people around him can be seen reacting to the first explosion … Bomber Two, virtually alone among the individuals in front of the restaurant, appears calm. He glances to the east and then calmly but rapidly begins moving to the west, away from the direction of the finish line. He walks away without his knapsack, having left it on the ground where he had been standing. Approximately 10 seconds later, an explosion occurs in the location where Bomber Two had placed his knapsack.

After the car chase with the Tsarnaevs, the police recovered “an intact low-grade explosive device,” as well as “two unexploded IEDs, as well as the remnants of numerous exploded IEDs.” Dzhokhar apparently has “gunshot wounds to the head, neck, legs, and hand.”

Ben Shapiro is Editor-At-Large of Breitbart News and author of the New York Times bestseller “Bullies: How the Left’s Culture of Fear and Intimidation Silences America” (Threshold Editions, January 8, 2013).