A bombshell revelation at the public inquiry into the Taser death of Robert Dziekanski has put the hearings on hold until September.

Just as lawyers were to begin their final submissions, government lawyer Helen Roberts submitted an internal RCMP email sent a month after the Polish immigrant was Tasered at Vancouver International Airport.

It suggests officers discussed using the Taser even before they confronted Dziekanski.

If true, that would contradict previous sworn testimony by the officers. All along the officers have maintained they did not discuss how they would respond to the call while en route to the scene, and had no plan to use a Taser before they confronted Dziekanski.

Lawyers for the officers say their clients stand by their original testimony.

Responding to the revelation, Inquiry Commissioner Thomas Braidwood said: "I find the delay in disclosing this material to the commission to be appalling."

Commission counsel Art Vertlieb said the email was handed over by the RCMP just this week, and he said the hearings need to examine the contents of the email and potentially call senior RCMP members and the four officers to testify again.

Government lawyer Roberts apologized to the commission in tears, saying she didn't reveal the email earlier because she believed the exchange involved a misunderstanding.

"On behalf of the government of Canada, I would like to sincerely apologize," she told the inquiry.

The government had the email since earlier this year. It involves an exchange between Chief Supt. Dick Bent and RCMP Assistant Commissioner Al McIntyre.

In Ottawa, Liberal public safety critic Mark Holland said the revelation is disturbing.

"If this is true, I think this is really going to shake the foundations of public trust in the RCMP," he said Friday.

Dziekanski died after being zapped with a Taser several times during a confrontation with RCMP officers. They claim he had been acting erratically and throwing furniture after he arrived at Vancouver airport in October 2007.

The incident was recorded by someone in the airport, and was eventually released online where it has been viewed tens of thousands of times.

The public inquiry, which began in January, 2008, has heard from more than 100 witnesses and has been a flashpoint for controversy.

For example, the officers who used the Taser against Dziekanski had launched a court challenge, arguing Braidwood didn't have jurisdiction to make misconduct findings against them, since he heads a provincial inquiry and the RCMP is a federal body.

Their lawyers also argued that allegations levelled against them in the inquiry -- that they acted improperly during the incident and then lied to cover it up -- are criminal offences and therefore can't be addressed in a public inquiry.

But the B.C. Supreme Court rejected the argument, leaving Braidwood free to reach findings of misconduct in his report.

The officers have not been charged in connection with the incident, and none of the report's findings will be legally binding in relation to the officers.

The officers made statements to the effect that Dziekanski was violent before he was Tasered -- a claim that seemed to run contrary to the amateur videos of the incident.

The inquiry will now resume Sept. 22.

With files from The Canadian Press