Naples : Gunmen shot dead Giovanni Sarno, the brother of Naples mafia informant Carmine Sarno overnight as he slept in an apartment in the city centre, police said. Sarno's niece identified his body at the apartment in Naples' Sanita district after an unnamed man rang on his relations' intercom at at around 4 a.m. to tell of the murder. Police have opened a probe into the slaying of 54-year-old Sarno, who was separated from his wife and was known to drink heavily, according to neighbours. Sarno's brother-in-law was previously murdered after the brothers decided to turn state's evidence against the Naples mafia and testified at the trials of several alleged Camorra clan members. Prime suspects in Sarno and his brother-in-law's murders are the Contini, Casalesi, Barra and Acerra clans, against whom the Sarnos gave evidence, Naples daily Il Mattino reported.