Investigators in Naples are examining a spate of armed robberies and burglaries of star players with the Napoli football team as suspicion grows that the city's Camorra mafia is plotting the attacks to pressure the club into sharing a slice of its profits.

Back in Italy's top division and through to the knockout stages of the Champions League after defeating Manchester City, Napoli have returned from years of underachievement, with the club's strikers becoming idols in the southern city.

But in less than three months the wife of forward Marek Hamsik has been carjacked, the partner of Ezequiel Lavezzi mugged at gunpoint, and Edinson Cavani burgled and his agent mugged – three of eight incidents involving players.

"The short space of time over which this has happened leaps out at you, which is why we are looking at these incidents with a certain interest," Luigi Merolla, the senior Naples police officer, told Corriere della Sera.

The Neapolitan academic and writer Biagio de Giovanni said: "It appears the mafia is targeting the Napoli players to get a piece of the team as it rises again."

Rumours are rife in Naples that, by increasing online ticket sales, Napoli have reduced the profits the Camorra took on street ticket sales, Corriere della Sera reported.

Giovanni Melillo, the magistrate investigating the attacks, downplayed mob theories, saying: "Anyone who goes around wearing expensive watches in an SUV in Naples has a high possibility of being robbed."

A spokeswoman for the club defined the attacks as "sporadic and not connected to organised criminals".

Melillo said it was "strange" that none of the jewels or watches had been returned. The Camorra located and returned to Diego Maradona watches stolen from him when he played for Napoli.

Investigators have long suspected links between the Camorra and the hard core "ultra" groups of fans following Napoli, who have been accused of seeking to blackmail the club into providing free tickets with threats of crowd violence.

After fans ransacked a train on their way to an away game in Rome in 2008, 200 of those questioned were found to have previous links to serious crimes including drug trafficking and robbery.

Napoli fixtures have also come to the attention of investigators examining allegations of mob gambling on matches.