The men had hoped to win compensation from the region for the incident, but investigators became suspicious when they discovered the wild boar that had allegedly caused the crash had a slit throat, local media reported on Thursday.
A vet called to examine the body found the animal's internal organs were frozen, suggesting the beast had been killed and stashed in a freezer before being strategically placed at the “crash site”, the Unione Sarda newspaper reported.
The two men risk a hefty fine and prison term of at least a year over the stunt, it said.
Wild boar (cinghiale) are a common sight on and near roads in rural or forested areas in Italy, and fatal car accdents involving the creatures have prompted calls for a cull in some regions.
In Lombardy alone, there have been around 400 road accidents involving the animals in the last five years, according to agricultural association Coldiretti.
In a freak accident in 2017, one man was killed after his scooter collided with a wild boar in central Rome.