Police have arrested four people on suspicion of accepting bribes in the awarding of contracts to rebuild the central Italian city of L'Aquila following its devastating 2009 earthquake.

L'Aquila's police squad director, Maurilio Grasso, told a news conference Wednesday that another four people are under investigation and that police searched the offices in city hall and L'Aquila's public health department where some of the suspects worked.

Police said $500,000 in bribes was paid to public officials to win contracts between 2009 and 2011.

More than 300 people were killed and thousands of buildings in L'Aquila and the Abruzzo region were damaged by the April 6, 2009, temblor.

One of those under investigation, Roberto Riga, said he is innocent but will step aside as vice mayor while the investigation continues.