The surprise last-minute qualifier in the race for 22nd Judicial District Attorney has withdrawn, leaving a four-member field vying to replace Walter Reed.

Robert B. “Robbie Rees had been something of a mystery candidate in the hotly contested race. He qualified on the final day, and reporters had been unable to contact him. He did not participate in either of the two forums that have been held so far, one hosted by Concerned Citizens of St. Tammany and the other by the St. Tammany West Chamber of Commerce.

Late last week, he slipped off the ballot just as quietly. Meg Casper of the Louisiana Secretary of State’s Office said that his withdrawal was registered at 1:42 p.m. on Aug. 29.

Rees could not be reached for comment Thursday.

The four candidates who remain in the race are Slidell lawyer Alan Black, Covington lawyer Roy Burns, Covington lawyer Warren Montgomery and Brian Trainor, who is on leave of absence from his job as chief deputy with the St. Tammany Parish Sheriff’s Office.

Reed, who is embroiled in investigations by a federal grand jury and the state Legislative Auditor’s Office, announced in July that he would not be seeking a sixth term.

Follow Sara Pagones on Twitter at @spagonesadvocat.