LONDON (AP) ― A criminal investigation into allegations of World Cup bidding corruption could be opened in Britain, with authorities urging whistleblowers to come forward with information.

The Serious Fraud Office is pursuing “every reasonable line of inquiry, including working closely with appropriate overseas authorities,” the government department said according to a letter sent to a British legislator.

The Swiss attorney general has already received a criminal complaint from FIFA against possible law-breaking by unnamed individuals mentioned in the investigation into the 2018 and 2022 World Cup bidding process.

Damian Collins, a member of the House of Commons culture, media and sport select committee, has been pushing the Serious Fraud Office to open an investigation. The Conservative Party parliamentarian also plans to meet two whistleblowers who provided evidence to FIFA prosecutor Michael Garcia for the corruption report.

“Plainly, the Serious Fraud Office welcomes any additional information that may assist in determining whether a criminal investigation should be opened,” SFO general counsel Alun Milford says in the letter to Collins seen by the Associated Press. “I encourage anyone with relevant information to come forward and discuss it, in strict confidence, with our Intelligence Unit.”

Milford provides an email address, saying it is “the easiest way for any whistleblowers to contact us.”