I'm a bit confused too. We're you with the guys that were racing?
Just because you did not see police there, doesn't mean they weren't looking. If an area becomes notorious for racing then don't be surprised if a pre planned op gets put in to target those putting people at risk.
To be fair to you, I'd not say anything else about the matter until-
A) You know if a prosecution will be mounted or not. And
B) You have sought legal advice.