Pizza boss 'prime suspect' 
EXCLUSIVE
Two of Italy's most senior anti-Mafia prosecutors have slammed Australia's policing of Calabrian organised crime as "inadequate" in the wake of the murder of lawyer Joseph "Pino" Acquaro, and warned that local authorities must do more or lose the fight against the secretive crime organisation.
Italy's top anti-Mafia prosecutor, Franco Roberti, has urged Australian police to immediately launch a joint investigation with Italian crime fighters into the killing of Mr Acquaro, who was gunned down on a Melbourne street on Tuesday. 
"This is the most serious crime and underscores the extreme danger that the Calabrian mafia, the 'Ndrangheta, poses in Australia," Mr Roberti told Fairfax Media.
"Gunning down a professional, a lawyer like Acquaro, sends the strongest message to Australians that the Mafia is particularly strong there.  I don't believe the authorities fully realise how dangerous this phenomenon is, and how widespread Italian organised crime is there."
Mr Roberti heads Italy's National Anti-Mafia Directorate in Rome. He said it was critical for Australian investigators to notify his office in Rome and regional prosecutors in Reggio Calabria, the capital of the southern region of Calabria, which is the stronghold of the 'Ndrangheta.
Mr Acquaro was shot dead while walking from Gelobar, his cafe and gelataria in Melbourne's inner suburbs,  to his black Mercedes sedan, at 12.55am on Tuesday.
The investigation will focus on the $200,000 contract placed on the head of Mr Acquaro, who was told by police detectives about the bounty last year, but ignored warnings to improve his security.
They will also investigate suggestions that the hitman flew in from overseas, after a high-profile Australian underworld figure refused to carry out the hit.
"I want to stress that this kind of murder underlines the necessity for Australian authorities to immediately notify Italian prosecutors and launch a joint inquiry into this murder," Mr Roberti said.
Asked whether it was possible that the killer was Italian and had already left Australia, Mr Roberti said: "That is definitely a possibility."
Italian authorities have repeatedly warned their Australian counterparts about the strong ties between the 'Ndrangheta and a number of Australian crime families.  
Mr Roberti's call for a joint Australian-Italian investigation was backed by leading Calabrian prosecutor Nicola Gratteri, who is based in Reggio Calabria.
Mr Gratteri, who must travel under armed escort due to the extreme threat to his life posed by the Mafia, has warned several times in the past year that Australian authorities underestimate the size, strength and spread of the 'Ndrangheta in this country.
He urged Australiato do more to fight the power of the 'Ndrangheta in the wake of the murder of Mr Acquaro.
"This is not like killing a rival criminal, this is the murder of a lawyer," he said. "This is a gravely serious crime. Police need to look deeply into this to understand what happened. I have not had any meetings or received information about the killing."
Detectives from Victoria Police's Purana taskforce have joined the investigation into the murder of Mr Acquaro, who had strong links with members of Melbourne's underworld.
The Purana detectives, specialists in Melbourne gangland criminals, have joined the homicide squad in the investigation into the shooting on Tuesday morning in Melbourne's inner east.
But Mr Gratteri and Mr Roberti both told Fairfax Media they had not been formally notified by Australian investigators of Mr Acquaro's death, despite their intimate knowledge of the Calabrian Mafia and their ties to families in NSW and Victoria, and the suggestion a professional assassin may have flown into Australia to perform the hit.
The shooting has now made headlines in a number of major Italian newspapers. Mr Gratteri said he had read about the murder  in Italian news reports, and stressed it was a "gravely serious crime". 
Last year Mr Gratteri said action to combat 'Ndrangheta in Australia was inadequate and the families that led the organisation were growing stronger.
He urged Australian judicial authorities to look at making Mafia association a crime, as it is in Italy. Similar anti-association laws have been passed in Australia to target outlaw motorcycle gangs.
 "I don't have the latest data, but I know that the Mafia has a strong presence in Australia," Mr Gratteri said. "There is also a presence in Germany, Canada and the Netherlands. It is the base that is needed and important that they have it."
Both Italian prosecutors have been successful in combating the Calabrian Mafia. 
This week 19 people with alleged links to 'Ndrangheta families were arrested in Calabria in an investigation that arose from the bombing of a local bar in 2014. This week's investigation dubbed "Sistema Reggio" revealed how five particular families control  Reggio Calabria, and businesses in the city.