Basically, here is the situation.
Colleague X broke a rule. Colleague X told me via chat that he broke the rule after I directly instructed him not to do so. I report Colleague X to the manager. I saved proof of the messages just in case. This rule Colleague X broke is relatively serious in our organization.
I feel like I did the right thing, but now I fear retaliation. Since I'm the only person that knows Colleague X broke the rule, if he's confronted, he's going to know I was the one that squealed. I fear that he'll simply make up stories and lies as a form of retaliation.
Can I do anything to protect myself or am I basically screwed if this person decides to make wild accusations? What should I have done differently?