Damir Skugor, a former executive at the INA oil and gas company who is a suspect in a HRK 1 billion (€133.3m) fraud case, was released from investigative custody on Wednesday evening after investigators from the USKOK anti-corruption office interviewed all the witnesses.

His former deputy Stjepan Leko and the CEO of the EVN Croatia Plin gas company, Vlado Mandic, were also released. They, too, had been remanded in custody to prevent them from interfering with the witnesses.

All three suspects would not talk to the press after leaving the Remetinec detention centre in Zagreb.

Investigating irregular sales of natural gas from INA, in mid-October USKOK widened its probe into Skugor, Leko, Mandic and businessman Goran Husic, suspecting them of causing HRK 3.5 million in additional damage to INA.

Leko and Mandic were arrested as part of a second line of inquiry into the gas sales scam. Their arrests were preceded by the arrests of Skugor, his father Dane, former Croatian Bar Association president Josip Surjak, his business partner Husic, and the former CEO of the Plinara Istocne Slavonije gas company, Marija Ratkic.

The previously arrested five persons are suspected of defrauding INA of more than HRK 1 billion (€133.3m) by purchasing gas from INA for €19.5 and then reselling it for as much as €210 per megawatt-hour.