The hearing of corruption charges against Pakistan cricketers Salman Butt, Mohammad Asif and Mohammad Aamer opened in Doha with the players facing lengthy bans if found guilty.
The hearing, being held behind closed doors at the Qatar Financial Centre, is scheduled to run until Tuesday although lawyers have indicated a verdict may come earlier.
The three face charges of spot-fixing during Pakistan's tour of England last year.
It's alleged that they conspired in the bowling of deliberate no-balls, claims they all deny.
They were provisionally suspended by the ICC in September, with the world governing body's code of conduct carrying a minimum five-year ban if corruption charges are proved.
The scandal came to light when Britain's News of the World claimed that seven Pakistani players, including Butt, Aamer and Asif, took money from a bookmaker to obey orders at specific stages in the Lord's Test in August.
Pakistan one-day captain Shahid Afridi and head coach Waqar Younis have been summoned as prosecution witnesses.