Antonio Brown Artist Accuser Claims AB Had Sex While She Painted In Same Room

Another allegation of sexual misconduct has come up against Antonio Brown ... this time, the artist who was hired to paint a mural in his home says AB had sex with another woman in front of her while she worked.

The artist, who has not gone public with her identity, was previously featured in a Sports Illustrated article about Brown, in which she claimed the WR got naked and hit on her while she was working at his home in 2017.

In the article, the woman says she declined his advances and felt he was being completely inappropriate ... but never went to cops or took any legal action against him.

After she went public, Brown allegedly sent her a series of menacing text messages as part of a group chat ... instructing associates to look into her personal life. AB included a photo of the artist's children, which she took as a clear threat.

In fact, the artist's attorney, Lisa J. Banks, sent a letter to the NFL saying her client is "understandably frightened by these text messages, which are clearly intended to threaten and intimidate her."

In the letter, Banks rehashes the initial sexual misconduct allegation featured in the SI article ... but then drops this additional allegation.

"What is not detailed in the story is that Mr. Brown engaged in other forms of sexual misconduct during the two days that she worked in his home, which included Mr. Brown having sex with another woman while the artist was working in the same room."

The NFL immediately launched an investigation into Brown -- who was cut the by the New England Patriots a short time later.