The Wall Street Journal, BY Alkman Granitsas

ATHENS—Greece is moving to effectively outlaw the extreme-right Golden Dawn party by asking prosecutors to declare it a criminal organization, days after police say a self-professed member confessed to killing a left-wing rap artist.The government presented prosecutors with a legal file late Thursday that it says shows Golden Dawn acted as an organized criminal gang—a felony under Greece's penal code—and declaring it a threat to public order.

The file is based on some 30 previous cases over the past year where members or followers of the party—which is known for its extremist views and tactics against immigrants, gays and political rivals—have been charged with illegal acts,

 

Many Greeks identify Golden Dawn as neo-Nazi based on its rhetoric and its swastika-like emblem—a label the party rejects. It has denied any connection to the recent killing and says it condemns violence against others.

Party chief Nikos Mihaloliakos has described the government's actions as a "witch hunt" and, on Friday, Golden Dawn lawmaker Ilias Kasidiaris said the party would sue Public Order Minister Nikos Dendias and others for defamation.

The impetus for the government action was the slaying early Wednesday of 34-year-old rapper Pavlos Fyssas. The police investigation has allegedly found a direct link between the party and the killing, a senior government official familiar with the matter said.

He and another senior government official say police investigators claim that Mr. Fyssas was set upon by a group of about 40 attackers that included a 45-year-old man, now in police custody, who police say confessed to stabbing the rapper. The man has said he was a member of Golden Dawn.

Since then, Greek media have published photos and accounts showing the accused man participating in party activities.

Significantly, police believe that the attack appears to have been organized. Phone records obtained by police allegedly show that the suspect arrived at the scene after receiving a series of calls and text messages, according to the two senior government officials. At least one of those communications appears to have been from Golden Dawn's local party boss in the district, the officials said.

The local party official couldn't be reached to comment.

If the move to have Golden Dawn named a criminal organization succeeds, something that isn't certain, it would mark the most serious blow to the party since it rose to prominence in the past several years, its popularity buoyed by Greece's protracted economic crisis and soaring unemployment.

The latest move comes amid growing calls—both within Greece and abroad—to ban the party outright, something that would be difficult under the Greek Constitution, which guarantees freedom of expression.

Greece's coalition government, dominated by the center-right New Democracy, has been slow so far to react to the rise of Golden Dawn. New Democracy, in particular, has been accused of soft-pedaling the threat posed by the group in an effort to lure back some of its traditional voters who have drifted to the far-right party.

New Democracy has dismissed the criticism, saying it was the first to condemn Golden Dawn's extremism. Rather, party officials say they fear that any move against the group could boomerang—driving its membership underground and perhaps boosting its popularity.

Far-right parties have been on the rise across Europe since the 1980s, but their support has grown in step with growing skepticism about the European Union, rising immigration into the bloc, and, most recently, the protracted economic crisis and tough austerity policies being enacted in many countries.

Germany, France and other countries have banned political parties they consider extreme, usually because of racist beliefs or involvement with violence. Those bans have met with mixed success: the outlawed groups sometimes reform within days under a different name.

But in Greece, the government is taking a different approach. If Golden Dawn is declared a criminal organization, the government would be able to prosecute any member of the group—including its entire leadership—regardless of whether they had any connection with violent acts.

"It's a very ambitious legal effort that we are mounting, but we are confident we have a very strong case that shows an organization structured to commit criminal acts," one of the officials said. "We believe that with this killing we will be able to practically outlaw the group."

Ultimately, the decision will rest with senior judges and could well involve lengthy appeals—as well as a decision by Parliament on whether to prosecute sitting party deputies.

Either way, the political calculus appears to have changed. "Under the existing penal code there are many things we can do that we have not done so far," said the second senior government official. "We are going to pursue this to the maximum under the existing laws and, if need be, we will enact new laws."

After six years of recession and 3½ years of harsh austerity measures, Greece has seen a radicalization of its political landscape.

Golden Dawn first entered the Parliament following elections in June 2012 and its popularity has risen since then. Recent public-opinion polls show it is the third-most-popular political party with 10% to 12% of the vote, trailing only New Democracy and the left-wing opposition Syriza party.

On Friday, Mr. Dendias, the public order minister, stripped Golden Dawn's 18 parliamentary deputies of police guards pending the outcome of the prosecutors' probe. Cases involving party members will now be handled by the police's elite antiterrorism unit, he said.

The killing of Mr. Fyssas comes after a series of violent attacks in recent days in which the government and police say Golden Dawn members went after political rivals, including communist activists and a center-right mayor in southern Greece.

Since Wednesday, protests against Golden Dawn have been held around the country, including one that drew some 5,000 people to the site of the killing in a working-class district of Athens. That demonstration later turned violent.

In keeping with Greek law, the police haven't released the man's name, but local media have identified him as Giorgos Roupakias. The suspect, who has been in police custody since Wednesday, hasn't yet been assigned a lawyer and attempts to reach family members at his home were unsuccessful.

On Saturday, he is expected to be deposed by an investigating magistrate, according to police sources.