An Italian mafia boss who disappeared last year was brutally beaten by members of a rival clan and then fed to pigs while he was still alive, a police investigation has revealed.

Detectives fighting organised crime in the southern Italian region of Calabria lost track of Francesco Raccosta, an affiliate of 'Ndrangheta, the local mafia group, in March 2012.

Police had reasons to believe that Raccosta was killed in retaliation for the murder of a rival boss, Domenico Bonarrigo, as part of a decades-long turf war between their two families for control of the rural village of Oppido Mamertina.

However, Raccosta's body was never found.

Clues on the mobster's demise were provided to police by Simone Pepe, an alleged hitman for the Bonarrigo family.

The 24-year old was heard bragging about killing Raccosta during a phone conversation tapped by police.

Speaking to another mobster, Pepe said he was part of a punitive mission against Raccosta. The mobster was kidnapped, led to a remote pigsty in the countryside and hit with iron bars and shovels, Pepe said.

"It was such a pleasure to hear him screaming," Pepe said on the phone. "Mamma mia, he was yelling so loudly."

Wounded and bleeding Raccosta was then given to the pigs as supper.

"He was already half dead; after three or four blows with the shovel his face had turned black," Pepe said.

"At the end there was nothing left. I couldn't see anything so I said: 'how avid is this pig!'"

The recording was disclosed by police after Pepe was arrested as part of a large anti-mafia operation this week.

Pepe, who is also accused of other three killings, was held in Oppido Mamertina along with another 19 suspected affiliates of the Bonarrigo clan, including an underage boy.

The arrested face a series of charges including mafia association and murder.

Authorities also seized 88 properties worth a total of more than €70m (£58m) located across Calabria and in Rome. Police allege their purchase was funded by the clan's criminal dealings.