The Miami-Dade County state attorney's office released a 27-minute secretly recorded tape in which the late rapper -- who was gunned down and killed back in June -- confessed to beating an ex and a lot more.

You hear XXX allegedly say, "I started f***ing her up bruh. I started f***ing her up because she made one mistake. And from there, the whole cycle went down. Now she’s scared. That girl is scared for her life. Which I understand.” XXX can later be heard saying, "I will kill that bitch if she play[s] with me."

As we reported ... XXX had been under criminal investigation for domestic violence and witness tampering. The case couldn't move forward following his death and it's unclear if the tape confession is related to those cases.

According to the tape ... XXX also talked about a January 2016 stabbing incident in Florida saying, "I'm on [Miami] New Times for stabbing, how many people they put in the news? They said three, it was eight." At the time, cops were reportedly looking for an unknown black male with tattoos on his face swinging a knife.

XXX also allegedly admitted to stabbing a former manager back in July 2016.