Photos sent to 7News by a viewer show the scene just before and right after the bombs went off on Boylston Street.
7News has provided these pictures to the FBI as they continue their investigation. They are looking at the pictures to see if it's possible it could be the second bomb.
In the first picture you can see a bag next to a mailbox and up against a barricade along the marathon route. In the second, which we have blurred because it is very graphic, there is no sign of the bag. The viewer who took the pictures says there may be an hour or more between when the first and second pictures were taken.
Related: Crime Scene Photos of Pressure Cooker Bomb Leaked.