Lisbon (AFP) – Portuguese police have rounded up a Russian mafia gang suspected of buying cash-strapped football clubs and using them for major money-laundering operations, law officials said Wednesday.

More than 70 police swooped on four clubs including Uniao de Leiria, as well as 22 homes and businesses in “Operation Matrioskas” on Tuesday, Europol and Portuguese law officials said.

Police also raided First Division clubs Benfica, Sporting and Braga although they are not directly part of the probe, named after the traditional Russian multi-layered nesting dolls.

“Active since at least 2008, this criminal network is thought to be a cell of an important Russian mafia group, directly responsible for laundering several million euros across numerous EU countries,” mostly from criminal activities committed outside the continent, Europe’s policing agency Europol said in a statement.

Police arrested three leaders of Leiria’s management company including its chairman, Russian former coach and footballer Alexander Tolstikov, a source close to the investigation told AFP.

The suspects are to appear before a judge on Thursday, the source added.

Prosecutors have also indicted a fourth suspect as well as the club itself and its management company as part of an investigation into “corruption, money-laundering and criminal association”.

Europol said red flags were raised by the “high standards of living” of the suspects, who imported “large amounts of cash from Russia to Portugal,” detected by law enforcement probing the case for more than a year.

The gang operates by marking and buying football clubs in financial distress through a complex network of holding companies registered in offshore tax havens, Europol added.

“Once clubs are under the control of the Russian mafia, the large scope of financial transactions, cross-border money flows and shortcomings in governance allow clubs to be used to launder dirty money,” it said.

This happened mainly through over- or under-valuing players on the transfer market, television rights deals and betting activities.

Uniao de Leiria’s team was briefly managed by Jose Mourinho in 2001-02 and it spent several years in Portugal’s First Division before finishing last in the 2011-2012 season.

The central Portuguese club then went bankrupt because of financial difficulties, leading to the resignation of 13 players because of wage delays.

Administratively relegated to regional level, the club managed to rise to the Third Division in 2013 and was bought in 2015 by Tolstikov.