Law enforcement sources tell us, Bari was traveling overseas and made a stop in London Tuesday. Turns out police knew his itinerary and arrested him at Heathrow Airport.

TMZ broke the story ... a woman sued him last November, claiming he attacked her last July at a London hotel, where some members of the Mob were staying. The lawsuit claims Bari burst into the woman's room and yelled, "You f****d my assistant, now you are going to f*** me."

She says she screamed no, but he pulled the sheets off of her. Bari's friend recorded the video and it got posted and went viral.

She says it didn't stop there ... she fled into a bathroom and he yelled, "I'm going to f*** you, you are going to suck my d***." He did not rape her, but she says he did throw her out naked into the hotel hallway.

What's especially interesting ... we're told Bari knew London cops were investigating the incident because they contacted him to come in for an interview. Nevertheless, he stepped into the danger zone by booking a flight with a London connection.