(ANSA) - Rome, December 16 - Rome city personnel chief Raffaele Marra, widely considered the right-hand man of Mayor Virginia Raggi, was arrested on Friday in relation to a corruption probe, sources said. The investigation regards real-estate transactions in 2013 when Marra was an official under a former administration in the capital. Carabinieri police on Friday searched the city-hall office of Marra after his arrest, sources said.

Raggi said Friday that she was "probably" wrong to have made Raffaele Marra her personnel chief after his arrest.

"We probably made a mistake," Raggi told a news conference. "Marra was a manager and we trusted him. I'm sorry for the citizens of Rome and the M5S".

The case is another embarrassment for Raggi and her anti-establishment 5-Star Movement (M5S), which prides itself on not being tainted by the corruption scandals that have hit other political parties. Earlier this week Raggi accepted the resignation of her former environment chief Paola Muraro after she was notified she was under investigation over alleged of unlawful waste treatment during her years as a consultant for city trash company AMA. On Wednesday police seized documents from city hall in relation to probe into nominations made by Raggi since she was elected in June. The mayor said Thursday she has "nothing to hide" over her appointments.

The presence of Marra, who for a spell was Raggi's deputy chief of staff, in the new administration had already caused unease among many in the M5S due to his links with Rome's former centre-right mayor Gianni Alemanno.

Construction and real-estate businessman Sergio Scarpellini was also arrested in relation to the same probe as Marra on Friday.

Scarpellini is suspected of corrupting officials to gain advantages for his businesses, sources said. Marra allegedly bought an apartment belonging to the Enasarco foundation for sales representatives in June 2013 with cheques linked to accounts of the real-estate businessman, according to the sources.

The Raggi administration's ability to address a range of big problems faced by the capital, including poor public transport, urban degradation and major issues with trash management, are widely seen as a big test of the M5S's ambitions to present itself as an viable alternative government at the national level.

