That finding is detailed in a lengthy Nigerian government report that has remained unreleased for five years, despite inquiries from the children's attorneys and from the media. The Washington Post recently obtained a copy of the confidential report, which is attracting congressional interest. It was provided by a source who asked to remain anonymous because of personal safety concerns.

The report concludes that Pfizer never obtained authorization from the Nigerian government to give the unproven drug to nearly 100 children and infants. Pfizer selected the patients at a field hospital in the city of Kano, where the children had been taken to be treated for an often deadly strain of meningitis. At the time, Doctors Without Borders was dispensing approved antibiotics at the hospital.

Pfizer's experiment was "an illegal trial of an unregistered drug," the Nigerian panel concluded, and a "clear case of exploitation of the ignorant."

The test came to public attention in December 2000, when The Post published the results of a year-long investigation into overseas pharmaceutical testing. The news was met in Nigeria with street demonstrations, lawsuits and demands for reform.

Pfizer contended that its researchers traveled to Kano with a purely philanthropic motive, to help fight the epidemic, which ultimately killed more than 15,000 Africans. The committee rejected that explanation, pointing out that Pfizer physicians completed their trial and left while "the epidemic was still raging."

The panel said an oral form of Trovan, the Pfizer drug used in the test, had apparently never been given to children with meningitis. There are no records documenting that Pfizer told the children or their parents that they were part of an experiment, it said. An approval letter from a Nigerian ethics committee, which Pfizer used to justify its actions had been concocted and backdated by the company's lead researcher in Kano, the report said.

The panel concluded that the experiment violated Nigerian law, the international Declaration of Helsinki that governs ethical medical research and the U.N. Convention on the Rights of the Child.

Five children died after being treated with the experimental antibiotic and others showed signs of arthritis, although there is no evidence the drug played a part. Six children died while taking a comparison drug.

The panel recommended that Pfizer be "sanctioned appropriately" and directed to issue "an unreserved apology to the government and people of Nigeria." The company should also pay an unspecified amount of restitution, the report said. The panel recommended that Nigeria enact reforms to prevent a recurrence.

Aspects of the affair remain mysterious, such as why the report remains confidential. The head of the investigative panel, Abdulsalami Nasidi, said in a brief telephone conversation from Nigeria, "I don't really know myself" why the report was never released.

"I did my job as a civil servant," said Nasidi, who is quoted in the report as saying he has been the target of unspecified death threats.