SAN SALVADOR, El Salvador -- The name is almost comically sinister, and Salvadorans are quick to share some gallows humor over "The Black Shadow."
But when the laughing stops, people who have suffered through death-squad terror and civil war acknowledge that there's something unsettling about this vigilante group called La Sombra Negra.
About three dozen murders, most committed against suspected criminals, have been attributed to The Black Shadow's "social cleansing" since the group became known in late February.
Coming in the wake of several unresolved political assassinations, the deaths are contributing to a renewed climate of fear in El Salvador. And they raise the specter of a new round of paramilitary violence in a nation aching to move beyond bloodshed.
"The fundamental point is impunity, and that has not been eliminated," said Celia Medrano of the non-governmental Human Rights Commission of El Salvador. "The death squads are still active."
The Salvadoran government and the just-departed United Nations observer mission contend that such slayings are mere remnants of the 12 years of war that ended in February 1992, a legacy that will not obstruct the Central American nation's manageable path to peace and prosperity.
Under the peace accords worked out by the United Nations, former army soldiers and ex-FMLN rebels make up two-fifths of the new police, while the rest are civilians.
But training the new officers has been slow and difficult, and the force is understaffed and outgunned by a growing criminal class.
Enter The Black Shadow.
Claiming that police and the courts are too corrupt or too weak to do their duty, the vigilante group has taken aim at street criminals, particularly gang members, and has threatened to execute six judges. One of those justices tried to resign but his attempt was rejected by the supreme court; all six now demand protection.
The death threats were sent directly to the offices of each of the six judges, raising speculation that Black Shadow members have a governmental connection. The group also bragged that it has "sharpshooters and bomb experts from special forces."
What human rights advocates like Ms. Medrano fear most, however, is that The Black Shadow will convince Salvadorans that there can be no security without a strong military or secret police.
Ms. Medrano believes that the Black Shadow, and groups like it, present the greatest threat to the peace accords because they undermine the legal, democratic institutions that mediators worked so hard to create.