Police in Portugal are planning to question Manchester United about the club's signing of striker Bebe from the Vitoria Guimaraes two years ago. The judicial police national unit for combating corruption, part of the Justice Ministry based in Lisbon, is investigating the August 2010 transfer, by which United paid $9.6 million for a player whose only competitive experience was a single season in the Portuguese third division. He played only two matches for United.

Alex Ferguson said at the time that Bebe was the only player he had signed in his long managerial career without having watched him at all first, even on video. United said Bebe had been recommended by Carlos Queiroz, coach of the Portugal national team, formerly Ferguson's assistant.

Bebe's agent, appointed days before Bebe moved to United, was Jorge Mendes, also agent to Cristiano Ronaldo, Nani and Anderson, who moved from Portuguese clubs to Old Trafford in previous seasons. Mendes was paid $4.6 million during the transaction. Last month, the police anti-corruption unit in Lisbon wrote to Bebe's former agent, Goncalo Reis, asking him to attend at their headquarters and as a witness to provide his account of what happened in the deal.

Reis has complained formally to the Portuguese Football Federation that Mendes improperly poached Bebe from him before very quickly sealing the United move, in breach of FIFA regulations governing the conduct of agents. Reis told the Guardian that police asked him in detail about every aspect of the transfer, and told him they plan to ask United for their version of the deal. Subsequently Reis emailed several documents to the inspector, including his contract to represent Bebe.