The first picture showing runners going past the monitor was actually taken from the BAA 5K race the 2 days before the Boston Marathon
If you go to the previous link, you can see a much larger version:
Scroll down to the photo and you will notice the timer is at 32:31 and underneath it says: 5K. The monitor is clearly seen.
This is the race link:
Here are the 2 winners at the Marathon:
At the upper right hand you can clearly see the edge of the monitor. Race time is 2:29:15.
A couple of hours later the bombs went off. Look carefully at the red, brick building and you will see the steel back of the monitor AFTER it has been taken down but not yet removed.
This correction neither proves no disproves the bombing was a hoax, I am merely correcting my first post.
I would say that the bombing actually took place the same day as the Marathon, not two separate films.
We have to be very careful when using someone else's research material. Even the most enthusiastic fighters make mistakes. I apologize to my readers for misleading them.