Streamer N3on Calls D4vd A 'F***ing Psychopath' After Finding Out They Met

N3on quickly put some distance between himself and D4vd after video emerged of the two meeting ... telling the guy he's not only going to jail -- he's headed to hell as well.

The streamer reacted to a video from one of his past streams where he met the alleged murderer ... watching the video in horror as he and the singer dapped each other up.

N3on goes into a total meltdown ... claiming he had no idea he ever met the dude -- and making it clear the interaction went down long before 14-year-old Celeste Rivas was found dismembered in the now-jailed singer's Tesla.

The YouTuber then goes on the offensive ... telling D4vd he doesn't care the guy's a fan -- he's gotta stop streaming ASAP because N3on doesn't want him in his corner.

N3on says D4vd's going to rot in jail ... before he rots in hell -- referring to him as an "absolute f***ing psychopath," and clearly trying to put as much distance between the two of them as possible

As you know ... D4vd was finally arrested and charged with the murder of Rivas in April, months after her maimed body was found in his car. A grand jury had been meeting since November, but hadn't returned an indictment against the star yet. Cops ultimately felt they had enough evidence to make an arrest.