BERLIN (AP) - The case horrified Germany, a nation where the Hitler era still casts a long shadow: a small band of neo-Nazis suspected of killing ethnic Turks and others in a seven-year terror spree, undetected by security forces until a botched bank robbery brought down the group last year.
Now, Germany's domestic spy agency faces awkward questions about a possible cover-up after revelations that an official destroyed files related to the neo-Nazi group. The case prompted the government to announce this week that the agency's head for the past 12 years will take early retirement.
Before he leaves, a parliamentary committee wants to question Heinz Fromm and the official responsible for the files on Thursday about whether the material was destroyed by mistake or deliberately.
The case had already proven deeply embarrassing to the agency, the Federal Office for the Protection of the Constitution, because of the failure to solve the killings of eight Turkish small businessmen and a Greek between 2000 and 2006 and a policewoman in 2007.
For years, authorities suspected organized crime rather than racist violence. Only when two suspected founding members were found dead last November after a botched bank robbery did the so-called National Socialist Underground's activities come to light.
Even though only a handful of people have been identified as active members of the group, the case shocked Germans: While concern about far-right violence flares periodically, there had never previously been anything like the campaign of murder attributed to the group. Nazi symbols and propaganda have been banned in Germany since the end of World War II.
Critics contended that as authorities concentrated on Islamic terror, they ignored the danger of ultra-right extremists. Relatives of victims said police tried to pin the murders on organized crime, drugs or ethnic rivalries, but never examined the possibility of right-wing terror.
The emergence of the ring prompted authorities to examine whether the group was linked to other unsolved crimes targeting immigrants; they suspect that it was behind a 2004 nail bomb attack in Cologne that injured 22 people, mostly of Turkish origin.
The failure to identify the Nationalist Socialist Underground despite nearly seven years of assassinations has served as a wake-up call to improve cooperation between Germany's tangle of federal and state-level security organizations - a system that has its roots in a desire to prevent any one authority having too much power after the repression of the Nazi era.
But the system also means different organizations are sometimes unaware of information uncovered by others, a problem which the U.S. found among American security agencies after the 9/11 attacks.
The German domestic intelligence agency, which recruits and oversees informers in extremist organizations, has faced much of the criticism over the neo-Nazi group.
That redoubled when it emerged last week that an official at the agency destroyed seven files, shortly after the lid blew in November on the National Socialist Underground and federal prosecutors asked other agencies to hand over information on the case.
Those files documented efforts years ago to recruit informers in another far-right organization to which the alleged National Socialist Union members once belonged.
"The public and lawmakers say, we want information, and instead documents were destroyed," Interior Minister Hans-Peter Friedrich said Tuesday. "It is important that we restore confidence."
He and lawmakers said it was unclear whether the documents were destroyed out of incompetence or as part of a cover-up.
A senior lawmaker with the opposition Greens, Volker Beck, said the intelligence agency "must now prove its necessity and capability through reforms and stronger democratic oversight."
The head of Germany's equivalent of the FBI, the Federal Criminal Police Office, told the parliamentary inquiry last week that "we failed." Joerg Ziercke pointed to complications in the federal set-up as a major factor.
Earlier this year, authorities set up a new center that brings together national agencies and representatives of the 16 states' separate intelligence and police forces to share information that might be of use in combating far-right crimes - something that was done years ago for Islamic extremism. In addition to the federal Parliament, some state legislatures have set up inquiries.
At the domestic intelligence agency, "there is a need for change and that will be done," Friedrich said.
"We must of course think fundamentally about the way this agency works," he said. "I think it always makes sense from time to time to think about the construction, work and mentality of authorities - whether it is up to date, whether things have to be changed."
On Tuesday, the regional government in Thuringia - the home state of the alleged group members - announced the removal of the head of its own intelligence agency. Thomas Sippel "no longer has the confidence" of the state legislature, regional interior minister Joerg Geibert said.
Adding to the embarrassment, it was not top-level intelligence but simple police work that uncovered the group's existence. After a failed bank robbery in the central city of Eisenach, police tracked the group's suspected founders, Uwe Boehnhardt and Uwe Mundlos, to a mobile home which was on fire when the authorities arrived. Both were found dead there in an apparent murder-suicide.
A third alleged core member, Beate Zschaepe, turned herself in and remains in custody pending trial.
Police found the murdered policewoman's service weapon in the mobile home, then discovered a pistol used in the businessmen's killings at a burned-out apartment used by the group and allegedly torched by Zschaepe.
Investigators also found copies of a propaganda video featuring pictures of the victims and a cartoon image of the Pink Panther standing next to a placard proclaiming "Germany Tour, 9th Turk Shot."
Zschaepe is accused of founding and membership in a terrorist organization. She has kept silent on the case while prosecutors prepare formal charges.