[batter]

He says he was across the street from the CVS. That would be a good place to start to ask for potential security cameras.

Interestingly enough, faq just mentioned that Treacher tweeted that the Police and the Secret Service have confirmed he was hit by the Secret Service. I wonder if those vehicles have dash cams?...

[faq]

An update says federal officials are claiming the SUV involved was a State Department security vehicle, not the Secret Service.