ROME

The wife and daughter of a former Italian member of the European Parliament (MEP) who is among four people detained in a corruption probe have been released from house arrest.

Pier Antonio Panzeri’s wife Maria Dolores Colleoni and daughter Silvia Panzeri were arrested on Dec. 9 as part of an investigation into one of the biggest corruption scandals in the EU's history.

It was reported Thursday that Panzeri started cooperating with the Belgian judiciary in the investigation, which impacted the decision by Belgian authorities, according to Italian channel Ranews24.

Eva Kaili, a Greek member and former vice president of the European Parliament, was arrested on Dec. 9 by Belgian police on corruption charges allegedly involving doing favors for Qatar.

Panzeri, a former S&D member of the European Parliament from Italy who chaired parliament’s human rights subcommittee, was also among those arrested.

He is one of the key figures in the investigation into suspected bribery at the European Parliament.

Although Qatar vigorously denies the allegations, so far, four individuals have been arrested and charged with "participation in a criminal organization, money laundering, and corruption," according to the prosecutors.