Several members of Parliament walked the same steps through Vancouver Airport on Thursday that Polish immigration Robert Dziekanski took in the hours before he died.

The House of Commons committee on public safety was hoping to find answers on the police use of Tasers, but the committee received little help from the RCMP.

"Explain to me how it came to pass that someone who has cleared all the security zones should have been attacked by a Taser,'' committee member Serge Menard asked RCMP Assistant Commissioner Al Mcintyre.

Mcintyre could supply few answers.

After reading a minute-by-minute account of Dziekanski's time spent at the airport in a report prepared by Canada Border Services, MP Ujjal Dosanjh wanted to know how the event was allowed to escalate so quickly.

"How is it with in the space of less that a minute of arriving on the scene an unarmed man in the presence of four police officers is Tasered?'' Dosanjh asked.

Mcintyre said he couldn't answer the question because both a criminal investigation and a coroner's inquest were still pending.

"We don't even know the official cause of death,'' he said.

"I'm sorry you're disappointed with my presentation,'' he told the committee members. "Please understand there are processes to follow.''

Dziekanski came to the airport on a long flight from Frankfurt, Germany, exhausted and confused, hoping to connect with his mother.

As MPs were walked through the same process as the would-be immigrant, a Canada Border Services Agency official said at no point was Dziekanski aggressive or angry with any CBSA staff during his ordeal.

A video taken of Dziekanski's confrontation with police shows him being shocked with the Taser, screaming in pain and then being held on the ground by at least two officers.

Dziekanski died in the early hours of Oct. 14 after the RCMP stunned him with the 50,000-volt Taser device.

A Vancouver airport official told the committee that exactly what happened to him in the hours before he was jolted with the Taser and died may never be known.

Michael O'Brien, vice-president of corporate security at Vancouver International Airport, said there was a gap of five hours when it's not known what Dziekanski was doing prior to his fatal confrontation with RCMP officers.

O'Brien said Dziekanski's whereabouts are not known because he was not seen on airport cameras.

But he also told the committee that there are other times when a camera shows the man seated on a bench inside the customs hall at the airport.

"For some reason, we're not sure, we may never know why, he went into the customs hall . . . and did not show up again on our camera views until 9:30 on Saturday evening,'' said O'Brien. "So for the next five hours he's somewhere down beside that customs hall, on a bench, we don't know.''

O'Brien said airport authorities have a theory as to why Dziekanski stayed so long in the baggage claim area before he was confronted by police.

"It is presumed, therefore, that he clung to: `I will wait by the baggage because those were the instructions from my mother.'''

His mother had driven to Vancouver from her home in Kamloops, B.C., having told Dziekanski she would meet him by the baggage carousel. However, she was not able to enter the secure area and left without reuniting with her son.

Committee chairwoman Penny Priddy expressed frustration at some of the comments about Dziekanski.

"I don't think Mr. Dziekanski thought he had any alternatives at all,'' she said.

"It's as if people have made a decision or an assumption ahead of time that he somehow had a role to play in his own death.''

In addition to the committee's inquiries, a public inquiry has been announced, the criminal investigation is ongoing and a coroner's inquest has been called.

Members of the public safety committee is holding two days of hearings as part of their investigation into Taser use. They are expected to meet with legal and medical experts on Friday.