Kroy Biermann Jr.‘s lawyer is firing back at claims prosecutors made about the 15-year-old in court … namely, allegations that KJ had videos on his phone showing him having sex with an underage family member.

Jason B. Sheffield is repping the son of “Real Housewives of Atlanta” star Kim Zolciak and former NFL player Kroy Biermann in his sexual battery case … and during Friday’s bond hearing, prosecutors made some shocking claims about a prior case, which was previously unknown.

Sheffield tells TMZ … “The characterizations made in court regarding the prior juvenile matter involving KJ Biermann grossly misrepresent both the facts and the ultimate resolution of that case.”

In addressing the videos, Sheffield said … “The matter arose from inappropriate, crude behavior involving two middle-schoolers.”

Prosecutors told the judge the videos showed penetrative sex and featured KJ using “predatory, derogatory” language toward the relative. They said he was charged with sexual battery of a victim under the age of 16 and the case was handled in juvenile court, which is why it wasn’t publicly known or reported on. Prosecutors said he’s been under court supervision for that charge since October 2025.

KJ’s lawyer said the prior case “did not result in an adjudication for statutory rape, sexual intercourse, or any comparable offense.”

He added … “Any suggestion otherwise is inaccurate and creates a materially misleading impression of how the juvenile matter was ultimately resolved.”

KJ’s attorney made similar claims while discussing bond conditions in court on Friday in his sexual battery case … admitting he hasn’t seen the evidence from the previous case — but, as he understands it, the video shows “more ridiculous, raunchy behavior” which is “boundary crossing inappropriate” but has resulted in group counseling and reunification.

As TMZ first reported, prosecutors revealed Kroy Jr. was previously accused of sexual assault in 2025 … before his recent incident … and was placed on probation as a result.