Criminal
Culprit
noun
A crime person is a criminal.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
犯人と議論したんだけど、中々かみあわなくってね。
I had an argument with the culprit, but I couldn't get anywhere.
その犯人は、口は災いの元だということを思い知った。
The criminal realized that the things he said truly were evil.
私は抜け目のない犯人にやられてしまったんだよ。私は全てを失って、犯人は指紋一つさえ残さなかったんだ。
I’ve been struck by a smooth criminal. I lost everything and he didn’t even leave one fingerprint.