This was pointed out before. Something about a drill. FWIW there has always been a security force for the Boston Marathon since 2001. Both at the gate and finish lines. Homeland security, FBI and state and local police are always in attendance. I haven’t watched the marathon live for about 5 years but the last time I was in the finish line area (my wife was running) the added security was quite noticable. If it was increased beyond what I saw back then something must have been up.
The police chief was having a press conference the day of the bombing. The first question was about a bomb drill. The second was about creating crisis to take out the Constitution. That was the end of the press conference.
The running coach of Mobile University (college) currently runs lots of marathons, and he was alerted to more security/monitoring presence than what he has ever seen. Initially, the ‘authorities’ tried to poo poo the idea that there was increase security presence. The regime lies, then layers more lies on the initial lies. We watched the clinton regime do it, the Bush admin do, and now we’re witnessing the most blatant use of layering of lies ever. I believe the running coach, since the rooftop ‘observers’ were caught in photos yet denied by ‘the authorities’.