As part of the 'O Negative' criminal inquiry, prosecutors are looking into suspicions that Lalanda e Castro, who was a director of Octapharma, and Cunha Ribeiro, who as head of INEM was involved in public healthcare procurement, had an agreement by which the latter would use his position and influence to benefit Octapharma unduly.

The two were released at the beginning of this month, thanks to a decision by Lisbon's criminal court, which also barred them from contacting each other or other persons of interest in the investigation, or from leaving the country, the presiding judge, Amélia Correia de Almeida, told Lusa.

Cunha Ribeira had been in custody since 17 December and Lalanda e Castro since 13 January.

The crimes under investigation in the case are bribery and receiving bribery, graft and money laundering - all relating to the business of buying and selling blood plasma.

The other persons of interest in the case are a representative of the Portuguese Haemophilia Association and two lawyers.

The case was being handled by Lisbon district prosecutors but because of its "special complexity" it has been transferred to the central criminal investigation department in the capital. The National Anti-Corruption Unit of the PJ criminal police is working on the case under the supervision of prosecutors.

Lalanda e Castro is also a person of interest in the 'Golden Visas' case, an investigation into suspected corruption in the administration of a government programme to fast-track residency permits for big foreign investors, and in Operation Marquês, a corruption investigation in which a former prime minister of Portugal, José Sócrates, is a suspect. Sócrates worked for a time as a consultant for Octapharma.