There is a surveillance camera that caught the explosion in Chelsea in New York City.
Watch below:
UPDATE:
Here’s another surveillance video from a different angle:
Surveillance video captures shocking moment of New York City explosion https://t.co/RAHzidYxdk pic.twitter.com/TPicrz2dUU
— ABC News (@ABC) September 18, 2016
We have an entire timeline of how the story developed on social media here.