(NewsNation) — Poker player Martin Kabrhel is responding to cheating accusations, saying: “I am not a cheater, this is not true!”

According to the Las Vegas Review Journal, the World Series of Poker is investigating Kabrhel after June 18’s Super High Roller Bowl that has a $250,000 buy-in. He reportedly finished in third place.

“While we do not discuss specific security protocols used to monitor players and gaming equipment, the integrity of the game remains paramount and we can assure fellow patrons that we are taking these allegations very seriously,” the WSOP said in a statement to the Las Vegas Review Journal. “As this is an ongoing investigation, there is no further comment on the matter at this time.”

American professional poker player Andrew Robl blasted Kabrhel on Twitter, claiming the challenger from the Czech Republic marks cards to have an edge on opponents.

“How is Martin Kabrhel not banned from the WSOP? He makes any tournament no fun for anyone and on top of it I’ve seen him mark cards in every tournament I’ve ever played with him,” Robl tweeted on June 18.

Kabrhel has denied the allegations and announced he is preparing to take legal action against Robl.

“This gossip is damaging me not only as poker player, but also my business activities and my family. That’s why I have decided to take legal action against Andrew Robl, because in such a professional tournament series as WSOP, it is very easy to prove such accusations are pure lies. I just can’t believe how easy it’s for people to join such accusations just by their personal antipathy towards my person,” Kabrhel posted on June 19.

Attorney Daniel Ravicher is representing Kabrhel. He published a letter on Twitter that was seemingly sent to Robl and four other Twitter users, calling the allegations “baseless.”

“He (Kabrhel) does not mark cards. You have said these false things with malicious intent,” Ravicher wrote in the letter. “We will prove this in court and ask that you be ordered to compensate him.”

Marking cards is a poker term for when someone marks the back of a card so they can recognize it without looking at its face. The World Series of Poker’s website says cards will always be considered a dead hand if they are marked or damaged in some way to prevent cheating.