Italian prosecutors believe pizza in the southern city of Naples might be baked in ovens lit with wood from coffins dug up from the local cemetery, the Italian daily Il Giornale reported Monday.

"Pizza, one of the few symbols of Naples that persists ... is hit by the concrete suspicion that it could be baked with wood from coffins," the newspaper said.

Investigators in Naples are setting their sights on the thousands of small, lower-end pizza shops and bakeries that dot the city on suspicion that workers might "use wood from caskets to keep ovens burning."

Naples' graveyard is a well-known hunting ground for thieves. Last year, 5,000 flower pots were stolen from the cemetery.

"A gang might have set up a market for coffins sold to hard-hearted owners of bakeries and pizzerias looking to save money on wood," Il Giornale said.

Neapolitan pizza was invented between 1715 and 1725, with the world-famous margherita variant first cooked up in 1889.

Tradition has it that Queen Margherita of Savoy asked one of Naples' famed pizzaioli to come up with a dish for the people.

The result, which provides the basis for most pizzas enjoyed around the world, represented the colors of recently unified Italy: green basil, white mozzarella and red tomatoes.

Italy's estimated 25,000 pizzerias employ around 150,000 people and account for a turnover of $6.5 billion.