British Grandmaster Danny Gormally and International Master Lawrence Trent both expressed doubts in the past year about the performance of Rausis on Twitter without directly accusing him of cheating.
Chess players can use powerful "engine" apps on mobile phones, such as the popular Chessbase app, to analyse games and find moves suggested by a computer. At most chess tournaments, the use of mobile phones is banned and even being in possession of one can lead to disqualification.
Many high-level tournaments require players to pass through metal detectors every time they enter the playing.
When he broke into the world's top 100 last year, Rausis was lauded as an example of how advancing age need not be a barrier to improvement in chess.
Russian Grandmaster and chess pundit Andrey Deviatkin said: "I always considered huge progress in chess to be highly unlikely after 30. But GM Igors Rausis, who is 57 (!), is now in the top 100, rated 2657.
"An exception that confirms the rule? Or the modern training methods plus persistence and passion for the game enable the impossible?"
However, while there is no evidence he cheated in the past, the allegations against Rausis have led to questions about his improbable rise.
Fide's Fair Play Commission Secretary Yuri Garrett revealed today officials had been "closely following a player for months" after a statistical model designed to catch computer cheats alerted them to Rausis' unusual performance.
Then at the Strasbourg Open, where Rausis stood to win 1000 euro if he won, the tournament arbiter alerted the commission to suspicious behaviour and officials were on hand.
It is, however, unclear what led to Rausis being pictured and whether it was a pre-planned operation or a chance encounter.
According to chess.com, Rausis later signed a declaration saying that a phone found in a toilet cubicle was his. Whether he was using his phone to get assistance from a chess engine has not been confirmed.
"The final result is finding a phone in the toilet and also finding its owner. Now the incident will follow the regular procedure and a trial will follow to establish what really happened," Garrett said.
"This is how anti-cheating works in chess. It's the team of the good guys against those who attempt at our game."
Approached for comment, Rausis said: "I simply lost my mind yesterday. I confirmed the fact of using my phone during the game by written [statement]. What could I say more?"