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.
I had an argument with the culprit, but I couldn't get anywhere.
The criminal realized that the things he said truly were evil.
I’ve been struck by a smooth criminal. I lost everything and he didn’t even leave one fingerprint.