Wow, it seems you really do have your facts together. Good.
I'm an ex-cop. (US Army and Army Reserve MP, 82-89). It's hard to stop being a cop, even though I haven't been one for 15+ years.
Found one more trick up my sleeve.
SOMEBODY called 911. Most likely, it was someone who saw it happen (and hopefully, it was one of the drivers stopped at the crosswalk). I spoke to the records section. For $5.00 and an FOIA request, I can get all the 911 info, including a recording of the call.