The terrorist who planted the second Boston bomb has apparently been caught on a security camera.
WHDH (Boston) has obtained some footage that may show what maybe the bomber running away from the scene after the blast.
Video obtained by the FBI shows the suspect placing a bag near the Lord and Taylor department store while talking on a cellphone moments before the twin blasts ripped though the city center, killing three and injuring more than 180.
The unidentified man is also captured using his phone at the moment the first explosion detonated 100 yards away on Boylston Street on Monday and 12 seconds before the second blast close to where he is standing.
He was wearing a black jacket, a grey hooded sweatshirt, is about 6ft or 6ft 2ins tall and of a medium build. He had a white or off-color-white baseball cap on backwards.
The footage led the FBI to announce it had made 'substantial progress' in the investigation, but stressed no-one has been named or arrested.
Investigators are reluctant to make the video public in case it forces the suspect to go underground.
In another key development, pictures have been released of a second potential suspect who is seen fleeing the site of one of the blasts as everyone around him cowers in terror clutching their ears.
Dressed all in black, the man's pants have been shredded and he hurriedly looks from left to right before making off in the opposite direction to the where members of the public are aiding the injured.
An FBI circular was sent out to law enforcement agencies last night seeking help to identify the two men.
According to CBS, investigators are now going through cell phone logs to determine who made calls from the location near the Lord and Taylor store the time of the explosions.
Read more: dailymail.co.uk/