Italian football midfielder Daniele De Rossi may have had dark thoughts on his mind when he took the field for Italy's lacklustre friendly against Austria last Wednesday. His 48-year-old father-in-law, Massimo Pisnoli, was recently found shot dead in what bore all the hallmarks of a gangland execution.

The Roma star and member of the Italian team that lifted the World Cup in Germany enjoys a lifestyle and income that banish all material cares. However, that was not the case for Pisnoli, a man with a criminal record for theft and burglary who, investigators believe, may have returned of late to a life of crime.

Pisnoli's body was found two weeks ago on a dirt road near the railway station for the small town of Campoleone, south of Rome. He had been shot in the back and then in the mouth - a classic sign of gangland punishment - and the body was unrecognisable after lying in the sun for several days. Relatives were able to identify him by his tattoos and the gold chain he was wearing around his neck.

De Rossi married Pisnoli's daughter Tamara shortly before the 2006 World Cup and the couple have a three-year-old daughter, Gaia.

Tamara is believed to have been in sporadic contact with her father, but reportedly helped him to find a new job in the hope it would distance him from the underworld milieu he is said to have frequented for years.

"We always tried to change him in so far as it was possible, but we never succeeded," Tamara told a television reporter. "It's true that he wasn't a saint, because he never was, but what people have been saying about him is absolutely untrue, that he was involved in extortion and drugs. We're not ashamed of anything. He's my father and we love him."

Confirmation that investigators were concentrating on an organised crime connection, rather than the victim's private life, came a week ago when the case passed from the hands of local prosecutors in Latina to anti-Mafia investigators in the capital.

Investigators are now examining the hypothesis that Pisnoli may have been killed in a dispute over the haul from an armed robbery. In particular, they are looking at two recent post office robberies in July and August, one in the capital and one in Aprilia, a fascist-era development not far from where Pisnoli's body was found.

The Corriere della Sera newspaper reported last week that scenes from the latter heist, in which two robbers got away with 120,000 (£95,000), were captured on closed-circuit TV. The robbers fled on a scooter but were later filmed transferring to a Lancia Y belonging to De Rossi's father-in-law, the paper said.

Investigators are also looking at the possibility that Pisnoli may have fallen foul of the Camorra, the Naples branch of the Mob that has steadily been encroaching on the agricultural lands and beachside resorts south of Rome.

"One of the lead concerns is the presence of the Camorra on the coast of Lazio," an investigator said. "This encroachment is something that has been going on for at least 30 years."

A separate investigation by Rome magistrates has been looking at the Mafia invasion of southern Lazio and found that the seaside resorts currently packed with holiday-makers - and the restaurants, bars, hotels and discos that make them buzz in the summer - are coming increasingly under the control of organised crime groups from Naples, Calabria and Sicily.

The invasion has been encouraged by the complicity of local politicians from the ruling Forza Italia party, who exchange administrative favours for political support, claim magistrates Diana De Martino and Italo Ormanni.

Opposition councillor Nicola Reale has denounced the infiltration of the Camorra and spiralling housing development around the picturesque beach resort of Sperlonga.

"Our town has fallen prey to omerta the Mafia code of silence," he told L'Espresso magazine last week. "When citizens want to make a complaint, they ask us to meet them inland. We have been subjected to intimidation. We are afraid here."

As if to confirm the climate of fear, newspapers reported on Friday that a local businessman had been shot in the legs as he sat outside his bar in the centre of Latina on Thursday evening.

The shocking murder of Massimo Pisnoli reminds Italians that their country faces more severe challenges than the one posed by Austria in last week's friendly, which, for the record, ended in a 2-2 draw.