The grisly discovery was made in the room, once used by gravediggers, at Maddaloni cemetery on Sunday, Il Mattino reported.
Two of the coffins contained corpses, while another – left open – contained a body that was “almost mummified”, the newspaper said.
The other two coffins in the room, which hadn’t been used for a year, contained bones.
They were found by graveyard staff who had gone back to the room to retrieve personal belongings, the newspaper said.
Police suspect the coffins might have been placed in the room while being transferred to a crypt, also called a funerary recess - a space built into a wall which is a common form of burial in Europe.
But they’re not ruling out other explanations, including “personal vendettas” against families of the deceased.
Rosa De Lucia, the mayor of Maddaloni, said the discovery was "disconcerting" and requires immediate clarity.
She also suspects that the bodies were removed from graves overnight.
“We ask the investigators to look into all the anomalies that have occurred in the cemetery over the past three years, including repeated theft, damage and disruption,” she was quoted Il Mattino as saying.