3 hours? Am I really supposed to believe that this story couldn't be told in an hour? Not bookmarking.
I would say the length of the video shouldn't be the basis for your decision. Look into the first video and judge the quality of the information. There is a lot evidence in the video that I was completely unaware of.
Another thing that was interesting was the number of websites that were published days before the shooting that were sending condolences to the families that lost children in the tragedy.