Updated

Portugal's Attorney-General's office says police have detained former prime minister Jose Socrates as part of an investigation into corruption, money-laundering and tax fraud.

A statement said Socrates, who was Portugal's prime minister from 2005 to 2011, was taken into custody late Friday with three others.

News channel S.I.C. Noticias said the former center-left Socialist leader was detained when he arrived to Lisbon airport on a flight from abroad.

The statement said the investigation is centering on bank transfers. Under Portugal's judicial secrecy law, no further details could be revealed.

The former leader's arrest is the third major scandal in four months, after the collapse of the country's largest listed bank, Banco Espirito Santo, and the recent arrest of the head of the immigration service in a corruption investigation.