Former Brentford and QPR striker DJ Campbell is among six people being questioned in connection with allegations of fixing in football matches.
The 32-year-old west Londoner, who scored 10 goals in 28 games during a six-month spell at Griffin Park, was one of six people arrested on Sunday.
Campbell left Rangers in the summer to join Championship rivals Blackburn following a disappointing two years with his boyhood club.
Blackburn Rovers FC said in a statement: "Following reports in today's national media, Blackburn Rovers can confirm that striker DJ Campbell has been arrested.
"The club will be making no further comment on what is now an ongoing legal matter."
The arrests came after another ex-Brentford player, Sam Sodje, who made 100 appearances for the Bees between 2004-06, allegedly told a reporter he could arrange for players to be booked or sent off in exchange for cash.
The National Crime Agency launched an inquiry after the Sun on Sunday passed on material from its own investigations.