Dzhokhar Tsarnaev did not plant the pressure cooker bomb at the Forum restaurant. His bag is well pictured in the famous video footage of the corner Gloucester/Boylston Street. It does not contain a pressure cooker (no bulge), it doesn’t fit the pictures of the remnants of the second bomb backpack, it doesn’t fit the FBI’s verbal description of the backpack, and Dzhokhar didn’t place it at the location where the second bomb exploded (it was 12-15 feet away, to be exact).
Notwithstanding, his behavior at the Marathon is a conundrum. He dropped his backpack in front of the Forum, and unless he “forgot” to pick it up when he left the site – which is highly unlikely – the question what was in his bag and why did he leave it there is extremely puzzling.
It is not disputed that Dzhokhar purchased and played with fireworks, opened the tubes and removed the black powder. But the producer has ensured that this black powder has not the explosive force necessary for a pressure cooker bomb.
It is also not disputed that there were some bomb alerts after the bombings. The Mandarin hotel was evacuated due to a bomb threat, and there was one controlled demolition announced one hour after the bombs, located across Boston Public library, which is exactly the first bomb site!
Reports from social media (unconfirmed) indicate that a secondary explosive device has been located outside of Boston’s Mandarin Oriental Hotel and will be destroyed (hopefully safely) in a controlled demolition by the Boston Police Department using explosive ordnance disposal equipment.
A third explosion was heard about an hour after the first two after authorities warned spectators to expect a loud noise from a water cannon that police apparently were using to destroy one of the devices.