Am I about to get fired from my 2nd job??

A bunch of employees(all underage) were about to go to a party and were drinking. They had open alcohol containers in the parking lot. I warned them when I was still on the clock not to drink and drive. They didn't listen.

When I left and was off the clock and off restaurant property in the parking lot they all piled in an SUV and were drinking with open containers and about to drive off, I called the police on them and reported their plate number. So they tried to transfer everything to a 2nd car and I reported that plate number too. Finally they got the help of a manager of the restaurant to hide their stash of alcohol so if/when they got pulled over they had nothing and would come back and get it later.

This all happened when I was off the clock and not on property. But the girls involved are shouting "harrassment" at me and told the manager who helped them stash away the alcohol I harrassed them by following them to their car when I was reporting the plate number to the police on the phone and yelled at them not to drink and drive in the parking lot and of course the manager agreed and is on their side. And apparently you can be fired for harrassment even off the clock and off property, as long as it involves employees.

Another manager on duty is the only one on my side because he lost his wife to a drunk driver. But I don't think he has a lot of pull as he is leaving in a few weeks because he thinks our management is incompetent. It will be my word and his against 3 girls, 2 guys, and the other manager who helped hide the alcohol. I am already on a short leash and I feel like I am finished. Our GM is the only one who can fire people and I feel like she will side against me if this gets brought up. My only hope is that no one cares enough to tell her about it but that won't happen.

And before you call me a snitch that needs to mind my own business I lost a girlfriend of 2 years that I wanted to marry to a drunk driver back in 2011 and had to go through 18 months of depression treatment. So frick off. I have no tolerance or respect for drunk drivers.