Erroneous statements by the four RCMP officers involved in Robert Dziekanski's death were nothing more than innocent mistakes, not a sign of a cover-up, says a lawyer for the federal government.

A public inquiry into what happened when Dziekanski was stunned with a Taser at Vancouver's airport has heard of numerous inaccuracies between a witness video and the statements officers gave to homicide investigators after the fatal encounter.

All four officers initially told investigators Dziekanski was yelling as they arrived at the airport arrivals area early the morning of Oct. 14, 2007, and moving toward them swinging a stapler.

They said he continued standing after the first shock and had to be wrestled to the floor.

But the Mounties recanted at the inquiry, where the witness video has been played again and again, refuting the version of events they gave before the video surfaced.

The lawyer for the Polish government has accused the officers of outright lying, but a lawyer for the federal government said Tuesday that is not the case.

"Much time was spent attempting to highlight the fact that there were some discrepancies and suggesting that there was some nefarious explanation," Jan Brongers told the inquiry.

"My point is that other witnesses, too, have had discrepancies between what they told police, and that there is a perfectly innocent explanation."

The officers made similar errors in the notes they jotted in their police notebooks at the scene, and in other internal reports about what happened.

When the officers testified at the inquiry over several weeks in February and March, they said they gave their best recollections of a fast-paced, stressful situation.

Crown prosecutors announced last December that Cpl. Monty Robinson, Const. Bill Bentley, Const. Kwesi Millington and Const. Gerry Rundel would not be charged in Dziekanski's death, saying they used reasonable force in the circumstances.

In announcing the decision, B.C. Criminal Justice Branch spokesman Stan Lowe said the officers' statements were "materially consistent" with the amateur video of the confrontation, although he didn't elaborate on that point.

The errors have led some, including Dziekanski's mother, Zofia Cisowski, to call for that decision to be reconsidered.

The province's attorney general, Wally Oppal, said prosecutors have the power to reconsider charges if they receive new evidence.

Oppal told The Canadian Press he was merely "talking theory," and cautioned that he hasn't seen anything so far that he believes could change the decision on charges.

"All I said is that if new evidence emerges, there's always a possibility to lay charges, but I didn't specifically say in this case it would happen," said Oppal, who has made similar comments in the past.

Oppal said he's "not prepared to buy in" that there was a significant change in evidence and there were false statements made.

The Crown has said it would be up to homicide investigators to decide whether to re-open the case. The RCMP has said the decision will have to wait until after the inquiry.

Walter Kosteckyj, the lawyer for Dziekanski's mother, said the officers' inaccuracies beg for a second look -- and that second look shouldn't be in the hands of the RCMP themselves.

"Look at the type of mistakes, how often they are repeated -- we're talking about professional witnesses. That is different than some individual who has never given evidence in court before," Kosteckyj said outside the inquiry.

"Whenever there is a police incident, it's high time we had completely independent oversight. We cannot have police investigating themselves."

Meanwhile, the senior airport supervisor on duty that night backed a controversial decision not to call the airport's own firefighters as Dziekanski lay on the floor dying after he was stunned.

Greg Sambrook said he wasn't involved in the decision, which was contrary to emergency protocol, but he supports it.

"The scene to me seemed to be a police scene, they were managing it, and I didn't see a need at that point for me to make a call to have ERS called," said Sambrook.