Dubbed “the General”, Mered Medhanie is alleged to have led a multi-billion dollar empire which specialised in people-smuggling.
A 35-year-old Eritrean, he came to public attention after being linked to the worst migrant disaster at sea – the deaths of 359 migrants in October 2013 after their boat sank near the Italian island of Lampedusa.
Canada-based barrister Christine Duhaime, who specialises in money-laundering legislation, said Mr Mered was suspected to be a ringleader of the people-smuggling network which stretched across Africa and Europe.
“He is notorious just for the fact that he controlled a lot of money and a lot of people,” she told the BBC’s Newsday programme.
“As kingpin, the amount of money that went through him is apparently in the billions.”
Italy’s Corriere Della Serra newspaper reports that Mr Mered has boasted of being in league with local officials in the Libyan capital, Tripoli, while also having a network of workers in Italy.
He charged migrants up to €5,000 (£3,900; $5,680) to travel from African countries to northern Europe, the newspaper said.
Mr Mered is said to have once lived in Italy, where he came under the radar of anti-mafia investigators after trying to open a bank account in Dubai.
He later moved to Libya, where most African migrants start the treacherous journey across the Mediterranean, and finally to Sudan, where he was arrested in the capital, Khartoum.
‘Nobody is stronger than me’
“It’s a good catch on the part of law enforcement. They’ve been following the money, and trying to track him down,” said Ms Duhaime.
The speed with which he was extradited from Sudan to Italy was “remarkable”, she added, something which usually happened when suspects faced money-laundering or terror-financing charges.
The UK Daily Mirror newspaper alleges his fixers also paid off Islamic State forces, which have gained a foothold in the North Africa state.
“When you are dealing with human trafficking from Libya over the Mediterranean and some parts of Africa there is obviously going to be an Isis connection,” Ms Duhaime said.
Mr Mered has not commented on such allegations.
British investigators supported the Italian inquiry into the Lampedusa tragedy, and it was the UK National Crime Agency (NCA) that tracked Mr Mered down with the help of the Sudanese police.
The NCA said he like to called “the General”, as he styled himself on the late Libyan leader Col Muammar Gaddafi.
He is said to have driven around in a tank and boasted: “Nobody is stronger than me.”
But by 2015, the investigators were closing in.
Italy issued an international arrest warrant for Mr Mered, a Christian, and revealed details of phone tap evidence it had obtained on him.
They depicted a man who, while kind and considerate when dealing with matters relating to his wife and children, who now live in Sweden, was cynical and ruthless in his work, Italy’s La Repubblica newspaper said.
In one intercepted conversation, he is reportedly heard laughing at the overloading of migrant boats.
According to Canada’s Globe and Mail, the recordings reveal he planned to invest part of his fortune in Canada and suggest his smuggling ambitions extended across the Atlantic, with one conversation offering €5,000 as the price to get to Canada using black-market passports.
According to the wiretap transcripts published in 2015, he boasted that business was good: “I’ve already sent off 7,000, 8,000 people.
“But this year will be better”.