QueenOfMassacre

There's a few griefers I know of, but one sticks out to me. Usually he goes by a similar name. But I have firsthand witnessed him be indecent in voice and in chat, and I've seen him use crashers, and even had him threaten to hack people, including myself. Is it appropriate to report him, even if it's after the fact? Is it okay to report his new alts when I spot them?