PS. The AP recycled their headline from last year.
MDA
Please show us the demographics of the murderer and the murdered.
Here is a link that has video of the march. It has been skilfully edited to make it difficult to get a good estimate of the numbers, and cuts away after about a hundred have been shown in the view.
Hard to say how many shown at the speaking event are actual participants.
All the close up shots are taken to give the impression of numbers without showing real numbers.
http://pix11.com/2016/05/07/families-march-across-brooklyn-bridge-to-rally-against-gun-violence/