The officials seized documents and electronic data during the Thursday raid, sources from the Greek judiciary said.

An unnamed official told the AP news agency that the move was a part of a preliminary investigation into a deal with KEELPNO, the Greek center for disease control.

The state-funded KEELPNO organized a cancer awareness drive in 2011, and the anti-graft teams are looking into the contracts with the companies involved. Earlier this year, the prosecutors charged a group of former KEELPNO managers with breach of duty.

The advertising company Mindwork Business Solutions Ltd, owned by Lina Nikolopoulou-Stournaras, is now under investigation on suspicion of wrongly securing a contract with the health body.

Governor not suspected

The businesswoman is married to the current head of the Greek central bank, Yiannis Stournaras, who previously served as the finance minister. The cancer-awareness drive, however, happened before he took office.

Lina Nikolopoulou-Stournaras has denied any wrongdoing. Her husband is not under investigation.

Yiannis Stournaras was part of the conservative cabinet led by conservative Antonis Samaras. Relations between him and the current left-wing government of Alexis Tsipras have been openly strained, with ruling party accusing him of not toeing "the national line" in the debt talks.

dj/sms (Reuters, AP)