Officials of The Philadelphia Inquirer National Sudoku Championship will retest a competitor as part of their investigation of possible cheating at the Oct. 24 finals.

Sources close to the investigation said yesterday that officials would meet next week in Philadelphia with contestant Eugene Varshavsky, who placed third in the advanced level, carrying a $3,000 prize. They will give him additional Sudoku puzzles to assess his ability to perform well, said the sources, who requested anonymity.

Varshavsky, who gives his residence as Lawrenceville, N.J., could not be independently located and interviewed.

The two officials at the head of the investigation are tournament director Will Shortz, crosswords editor of the New York Times, and Nick Baxter, director of judging and puzzle selector for the Inquirer event. Shortz and Baxter just returned from the World Puzzle Championship in Turkey last week. "We expect to have a conclusion to all this soon," Shortz said.

Matthew Banker of Indianapolis competed in the Inquirer event. He said in an e-mail that the organizers "do a very good job" but that "it became clear this year how lax the regulation of this event had [become] from a security standpoint. People could easily use electronic devices to solve the puzzles."

Competitors at the event have speculated that Varshavsky, who wore a hooded sweatshirt throughout the competition, could have concealed an electronic device that aided his performance.

"Having traveled from the Midwest to compete," Banker wrote, "it's disheartening to know many folks spent time and money to participate in this event . . . and for the judges [and] event supervisors to not know someone is cheating when they are right in front of you is amazing."

Banker writes that "banning electronic devices may be necessary" and that he knows of programs and devices that can solve puzzles or send them remotely to outside players.

Chess player Phil Irwin says he thinks Varshavsky is the same person whose play and behavior were questioned during the July 2006 World Open chess tourney in Philadelphia.

Irwin played Varshavsky in the National Open in June 2006, two weeks before the World Open. Irwin wrote by e-mail that players of their level usually start with simple opening moves and wait for an opponent's blunder, but "during our game he played some very bizarre opening moves and then eventually quickly finished me off with a very sophisticated combination. He arrived late to the game and kept his neck cocked at the same angle for long periods. Later I wondered if he had a camera in his stocking cap, which he wore along with a heavy sweater in Las Vegas in June."

Later, Irwin checked Varshavsky's moves against a computer chess program called Fritz and found that "his winning line of play is suggested by my Fritz computer and seemed to come from nowhere."

At the World Open, Varshavsky tied one grand master and defeated another. Grandmasters "almost never lose" to players of Varshavsky's level, according to Irwin. During the competition, Varshavsky was questioned about his methods and unlikely success. Eventually he was allowed to play the next round and lost.

Irwin saw a photo of Varshavsky at the Inquirer event, said he looked "familiar," and identified him as the same man he faced in 2006.

Contact staff writer John Timpane at 215-854-4406, jt@phillynews.com, or twitter.com/jtimpane.