The allegation resulted from a probe into the culpable cause of an epidemic by the Lombardy chief, ex-Prime Minister Giuseppe Conte, former Health Minister Roberto Speranza and 19 others.
Fontana is alleged to have caused "the spread of the epidemic" in the Seriana Valley near Bergamo.
The Bergamo Public Prosecutor's Office estimates the preventable deaths of 4148 people, they said in a notice of investigation.
They believe this number is “equal to the number of fewer deaths that would have occurred if the red zone had been extended from February 27 2020”.
Bergamo Chief Prosecutor Antonio Chiappani said an emergency decree on February 23 made it possible to shut off specific areas to contain the spread of the virus.
Investigators claim Conte, Speranza and other top officials underestimated the contagiousness of Covid-19, failing to isolate Nembro and Alzano Lombardo, two areas hit hardest by the outbreak.
“There was an insufficient assessment of risk,” said Chiappani.
Meanwhile Fontana criticised the fact that he learnt of his suspect status from the media during an interview on Radio Anch'io on Thursday morning.
"It’s a disgrace that a person who was heard at the beginning of the investigation as someone with knowledge of the facts finds out from the newspapers that he has been turned into a suspect,” he said.
ANSA
