In 2005, after the failure of an agreement with Forza Italia, he ran for regional elections in Campania on the list of Gianfranco Rotondi, the Christian Democracy for Autonomies.

On 7 June he was elected President of the Defense Commission thanks to an agreement with the House of Freedoms reached directly with the mediation of the Senate leader of Forza Italia, Renato Schifani, in contrast to the candidate of the Union, the ex-partisan Lidia Menapace.

[1] On 8 April 2008 he was entered in the register of suspects of the Reggio Calabria district anti-mafia prosecutor's office for external competition in association with mafia-type crimes aimed at recycling.

According to the indictment, Lavitola "as the de facto owner and co-director of the International Press" company that manages the newspaper, and De Gregorio "as effective shareholder since 1997 and co-director of the same company, have shown that the publisher of the L'Avanti!, possessed the legal requirements to obtain the contributions provided for by the law for publishing: a total of 23 million and 200 thousand euros received from 1997 to 2009 including false assumptions.

On 16 April 2012 a precautionary custody order was issued under house arrest against him by the prosecutor's office of the Republic of Naples, again with reference to the misappropriation of 20 million euros in loans to the daily newspaper L'Avanti!.

[4] On 11 March 2013, speaking with journalists about his involvement in the investigation into the alleged sale of the senators, De Gregorio publicly admitted that he took two million euros in black and committed a crime, therefore.