Volkswagen AG Chairman Hans Dieter Poetsch told reporters the company still believes a "comparatively small" number of employees were directly responsible for the illicit software, which he said was enabled by process failures and elements within the company that tolerated rule violations.
"The key finding," Poetsch said through an interpreter, "is that we are not talking about a one-off mistake but a whole chain of mistakes that was not interrupted at any point along the timeline."
VW has promised to put "everything on the table" following an investigation that it bills as comprehensive in scope and thorough in detail, one that will spare no guilty party from blame, no matter how high up the food chain.
Some 450 internal and external investigators are at work, combing through the equivalent of 50 million books' worth of data, VW said. They have conducted 87 interviews, with dozens more to come, and have collected 1,500 hard drives, cellphones, memory sticks and other data sources from some 380 employees.
It will take time to comb through that vast pool of data, VW said. In summarizing the progress of VW's own inquiries, Poetsch said nine managers who "may" have been involved in the emissions manipulations have been suspended so far. Other top officials have already resigned, including former CEO Martin Winterkorn and Audi r&d boss Ulrich Hackenberg, who reportedly was suspended shortly after the emissions violations surfaced in September.
The external probe, led by U.S. law firm Jones Day, will have to meet strict legal tests in assigning blame for the malfeasance and is expected to take several months more to complete. An update is planned for VW's annual meeting next April. That would be about seven months after the deception became public.
That pace indicates that it could be a long time before Volkswagen is able to bring some degree of closure to a scandal that has battered its global reputation and frozen sales of diesel vehicles in the U.S.
By comparison, General Motors was on a faster track with its investigation last year into the long-delayed recall of a defective ignition switch, a matter that had been pingponging through its engineering and legal operations for more than a decade.
GM announced the recall Feb. 13, 2014. Weeks later, it hired Anton Valukas, a former federal prosecutor, to conduct an internal probe of the matter.
The findings and a package of recommended reforms were made public in a 276-page report by early June, along with the firings of more than a dozen engineers and lawyers.
In the meantime, it hired victim-compensation expert Kenneth Feinberg to develop and administer a program to pay crash victims. That compensation fund is only now finishing its work.