Germany was running a fast check Thursday of DNA from a convicted Italian mobster held in Amsterdam to see if it matches a trace found last year in a getaway car, dpa reported.
Giuseppe Nirta, 35, who is the number-two suspect in a gangland-style slaying of six men in Duisburg, Germany, was picked up this week by Dutch police. He is also wanted in Italy to serve a sentence of 14 years, 8 months for drug trafficking.
Germany is still hunting the prime suspect, pizzeria operator Giovanni Strangio, 29.
Both are suspected of being senior members of the Strangio-Nirta clan within the 'Ndrangheta crime network in Calabria. The victims were believed to be members of the Pelle-Vottari-Romeo family, a rival mafia clan.
Police had recovered what they believed to be genetic traces from Nirta, nicknamed Charlie, in a black Renault Clio car found abandoned last October in Belgium and his fingerprints in an apartment in Dusseldorf.
In Duisburg, an industrial town that was rocked by the August 14, 2007 killing at the Da Bruno restaurant, police declined comment on a report on WDR television that the DNA smudge does not match a sample provided by Nirta relatives in Italy.
Duisburg police applied to Amsterdam police to obtain a scraping from the inside of Nirta's cheek to establish his identity. They reportedly regard Nirta as an accomplice rather than the assassin.
But witnesses saw two attackers fire about 70 bullets at six victims aged 16 to 39 as they were leaving the restaurant.
One of the Duisburg victims was a chief suspect in the December 2006 murder in San Luca of Maria Strangio, the wife of the suspected leader of the Strangio-Nirta clan and cousin of Giovanni Strangio.
The Calabrian town of San Luca has long been considered by authorities as a hotbed of 'Ndrangheta activity.
Italian news reports say Italy itself hopes to obtain Nirta's extradition within weeks.