Of course you should contact the FBI. You won't get in trouble so why hesitate. I can't speak for Dan, but I am close to 100% sure that unless Paddock was a registered user of the forum there is no way to detect if Paddock visited here.

Look be realistic. The FBI needs everyone's help. It doesn't hurt to provide this. At worst, someone will say "thank you for calling."

Also, I think you have found some parallels that are very interesting.

Another reason for YOU to contact the FBI is that I am sure the FBI is not monitoring this forum.