ROME (AP) — The ringleader of a gangland style massacre of six people in Germany was convicted and sentenced to life in prison on Tuesday for an attack that highlighted the international reach of Italy's Calabrian mafia.

Giovanni Strangio, 32, was one of eight people convicted and given Italy's stiffest sentence for their roles in a violent feud that culminated in the 2007 slayings in the western German city of Duisburg, the court clerk's office in the southern Italian city of Locri said.

Three other people were convicted and sentenced to terms ranging from nine to 12 years, while three more were acquitted, the court said.

Six Italian men were gunned down Aug. 15, 2007, as they left a birthday party at an Italian restaurant in Duisburg. Prosecutors said the massacre was part of a long-running feud between two clans of the 'ndrangheta organized crime syndicate, which is based in the southern Italian region of Calabria.

The 'ndrangheta is today considered more powerful than the Sicilian Mafia and has become one of the world's biggest cocaine traffickers.

The feud, which pitted the Nirta-Strangio families against the Pelle-Vottari-Romeo families in the tiny Calabrian town of San Luca, cooled from 2000 to 2006 but erupted again when Maria Strangio, the wife of one of the presumed heads of the clan, was killed on Dec. 25, 2006.

Giuseppe Strangio, Maria's cousin, was arrested in 2009 in Amsterdam on charges he masterminded and executed the Duisburg massacre in retaliation, one of the first known times the 'ndrangheta had exported a vendetta.

Italian law allows prosecution of crimes that occur in other countries if Italian citizens are the victims.

Prosecutor Nicola Gratteri welcomed the convictions and said they made clear that the 'ndrangheta has spread its tentacles outside of southern Italy.

"This has caused a lot of harm, not only to Calabria but also to the image of Italy, at least in central and northern Europe," he said after the verdicts were read out.

Inside the courtroom, mothers of the victims wailed as the sentences were handed down, particularly against Strangio.

"If he is the one who committed this crime it's fair that he pays for this because he's alive and will be back in a couple of years, but my son will never come back again, as any of the other sons to their mothers," said Antonia Giorgio Marmo, mother of victim Marco Marmo.

Marianna Carlino, the mother of slain brothers Francesco and Mario Pergola, said her life was shattered on Aug. 15, 2007.

"Nobody will return my sons to me, but one thing is for sure, at least from today onwards my two sons and the other four victims can maybe rest in peace at least partially, since justice was done."

Ralf Jaeger, the interior minister of North Rhine-Westphalia, the German state where Duisburg is located, praised the strong cooperation between Italian and German police that helped make the verdicts possible.

"It proves that international cooperation in the fight against organized crime works," Jaeger was quoted as saying by German news agency DAPD.

Copyright 2011 The Associated Press.