The sources cited court documents filed ahead of the first hearing of their trial scheduled on November 5.
Prosecutors Federico Manotti and Luca Monteverde believe the corruption allegedly took place during an electoral dinner held on April 14, 2024, at Villa Lo Zerbino in Genoa.
Their alleged goal was to raise funds ahead of regional elections originally scheduled for 2025.
The dinner was attended by 10 people who worked for Spinelli for a cost of 4500 euros, according to the documents.
The November case regards alleged bribes in which cash for an election campaign was exchanged for favours, including the extension of a port terminal concession.
Toti, who stepped down as governor last month, faces charges of corruption and illicit financing while Spinelli and Emilio Signorini, the former chairman of the Western Ligurian Sea Port Authority, are accused of corruption.
ANSA