Web bookmaker Betonsports has sacked its chief executive David Carruthers following his high-profile arrest in Dallas last week.
The company, which faces racketeering and fraud charges in the US as part of a crackdown on web gaming firms, said it had ended Carruthers' contract and removed him as a director.
In a statement, it said it had been unable to speak directly with Carruthers since his detention, only through lawyers: "Clearly, while he remains in the custody of the US government, he is unable to perform his duties," it added.
Directors including Chairman Clive Parritt, Finance Director Richard Creed and non-executive director Chris Callaway are now managing the company, spokeswoman Hannah Seward told Bloomberg.
Carruthers was arrested last week while changing planes at Dallas airport en route to his company's base in Costa Rica, and is now in a Missouri prison.
Betonsports has been ordered to return its takings from the US, where online gambling is considered illegal. Its shares have been suspended since July 18, the day after the company and its chief executive were indicted. The stock fell 17% the previous day.
The company said it was evaluating all options and deciding what measures to take next. "Since the time of its public listing, the board believes the company has operated in accordance with the standard expected of a UK Plc which is publicly quoted on AIM on the London Stock Exchange."
According to the Mail on Sunday, investors are considering legal action against the company and its advisors.