MLB umpire, Brian O'Nora, was arrested in a sex sting operation in Ohio this weekend ... after officials say he tried to solicit a prostitute online.
57-year-old O'Nora -- who's been an MLB umpire since 2000 -- was 1 of 14 alleged "Johns" who went online seeking to illegally purchase a sex act, according to police.
But, O'Nora didn't get sex ... instead, he got nailed by the Liberty Township Police Department, which was working with a task force that specializes in busting human trafficking operations.
Details of what exactly went down during the sting operation are unclear -- we're working on it -- but O'Nora and the others were all arrested and charged with misdemeanor soliciting and misdemeanor possessing criminal tools.
"John stings deter those seeking to purchase sex -- reducing the demand for human trafficking -- and serve as a reminder that these crimes are more prevalent and closer to home than you may think," Ohio Attorney General Dave Yost said Monday.