I Bullied Someone And Now I Feel Bad

I recently graduated but during highschool there was a kid that people picked on and I made fun of him too because I was afraid of losing my popularity and get bullied alongside him. I feel bad for it and tried to talk with him but he just threatened me by saying that he was going to get revenge starting with me by r*ping and impregnating me when I least expect it. I wasn't even the first person or the person who bullied him the most. I'm a little scared he might make turn his threats into reality. I don't think the police could do anything if it's my word against his, and I might get into trouble for bullying too. I told my best friend but she thinks it's an empty threat. What do people think?