I work for a security company that contracts us guards out to amusement parks and museums.  About a week ago I got a call from my boss asking me if I had seen any employees running on the indoor track at night.  Their policy is only park guests are allowed to use any facility that are for guests.  I don't remember seeing anyone, and the park is open to 2am, so I didn't think it was a big deal.  A day later I got a call from the head cheese(the ex-SS guy) telling me he viewed the CCTV footage outside the gym complex, and it shows me going in to the complex one minute after the park employee.  The video does not show me interacting with the employee.  It only shows me going in to the same 5 room complex.  So the two likely scenarios are: I either didn't see him, or I did and just didn't recognize him as an employee since he works swing shifts.

I guess the employee said I came in, saw him running and said it was OK.  Now the big boss ex-SS guy is going to interview this employee, and then me.  Under most circumstances I would just quit since I was looking for a low stress job until I get hired on with the Prisons.  But I don't want this SS guy who takes his job way to seriously to get away with branding me a liar.  Also I get a SSBI update every 5 years at this prisons job I'm trying to get and I don't want this asshole casting suspicion on me to keep himself from looking bad.

What should I do in this situation?

If I knew he was an employee I would have reported it in my log.