Toronto — Explosive new evidence “fundamentally explains” why police shot and killed an unarmed aboriginal protester nine years ago and should be released immediately, a lawyer for the dead man's brother said Friday.

However, Murray Klippenstein said he couldn't release the audio tape because it was given to the public inquiry looking into the killing and he had signed a confidentiality agreement.

But Mr. Klippenstein said the evidence was too important to be kept secret, so he intends to ask the inquiry to allow the material to be made public now.

He said the evidence had been “concealed from the family, the courts and the public for nine years” but would provide answers long sought by the family of the dead man.

“We believe [the material] is fundamental to understanding the death of Dudley George,” Mr. Klippenstein said.

Such an understanding is at the heart of what the inquiry under Justice Sidney Linden is hoping to achieve.

Ontario provincial police killed George in September 1995 when they moved in on a group of unarmed aboriginal protesters occupying Ipperwash provincial park on Lake Huron.

There were immediate questions about the circumstances of the killing, which ultimately led to a criminal conviction against the officer who pulled the trigger.

There were also allegations, always strenuously denied, that police acted the way they did under pressure from former Conservative premier Mike Harris and his government. A tortuous lawsuit against Mr. Harris filed by some in the dead man's family was dropped last fall when the new Liberal government called the public inquiry.

Mr. Harris will be a witness at the hearings, most of which are being held in the town of Forest in southwestern Ontario.

Sam George, the brother of the slain protester, said he had heard the tape and found its contents disturbing.

“The taped evidence that I heard saddened me. It also frightened me,” he said. “What I have now heard goes a long way to explaining why my brother Dudley was killed.”

Mr. George and his lawyers say it's now obvious why the tape remained secret for so long and raised the possibility that criminal proceedings could flow from its suppression.

The tape was released to all parties involved in the hearing under the same confidentiality rules.

Mr. Klippenstein said the contents would come out at the inquiry, which is now in its early stages. But he said they were too important to be withheld until then.