Pakistan's cricket authorities are investigating reports that banned spinner Danish Kaneria played in an exhibition tournament in the United States last week.
Back in 2012, Kaneria was found guilty of spot-fixing when representing Essex and was subsequently banned from playing cricket anywhere in the world under ICC rules.
However, it has now been revealed he represented the Houston Eagles in a series of T20 games in Texas, along with Test players Wahab Riaz and Nasir Jamshed who were members of rival team Boom Boom Blasters.
Other Pakistani players involved in these matches, and also being investigated, are Fawad Alam, Abdul Razzaq and Shahzaib Hasan.
Pakistan Cricket Board operating officer Subhan Ahmed admitted: "We are looking into how these players featured in these matches - authorised or unauthorised - without our permission."
The United States of America Cricket Association could also have questions to answer as banned players, such as Kaneria, are not allowed to take part in any match under the auspices of an ICC member country's association.
Kaneria, now 33, was found guilty of spot-fixing during a match between Essex and Durham in September 2009.
In the same Pro40 game, his Essex team-mate Mervyn Westfield agreed to concede a specified number of runs in one over in a match televised live in England and parts of Asia.
Westfield, who accepted he had received £6,000 for doing this, was jailed for four months in February 2012.