The manufacturer of Taser guns has posted a new training bulletin on its website recommending that officers avoid firing at the chests of suspects.

The bulletin says it is not possible to predict or test whether Tasers do or don't affect the human heart.

"In order to increase the safety margin and since field experience shows that (Taser) discharges are effective when deployed to the large muscles of the back, abdomen, legs and pelvic triangle, users should aim for the back or when practical toward the mid lower abdomen and avoid intentionally targeting the chest area," the bulletin from Taser International states.

The lawyer representing the family of Robert Dziekanski, who died after being hit in the chest by a Taser at Vancouver International Airport and whose death spurred a public inquiry, said the warning comes too little, too late.

"The inquiry in the first phase did find that there could be direct capture of the heart, as a result of the use of the Taser. That is something that has always been denied," said Walter Kostecky.

"Now Taser by implication is admitting that it causes death, that it is a very serious weapon and that it should be used under more strict guidelines."

Police in Vancouver say they have already notified their officers about the warning.

There is no word yet from B.C.'s solicitor general or the RCMP on whether this will become a province-wide policy.

Lawsuit filed

Meanwhile, Dziekanski's mother filed a lawsuit Wednesday alleging excessive force and "cruel and unusual" treatment by the four RCMP officers who stunned her son with a Taser.

Zofia Cisowski is suing the four officers, the Canadian and British Columbia governments, and the Vancouver airport, where Dziekanski collapsed and died after being stunned by Mounties in October 2007.

The lawsuit alleges everyone involved failed Dziekanski in some way.

"Mr. Dziekanski died as a result of injuries he sustained in the assault and physical restraint by the RCMP members," says the statement of claim filed in B.C. Supreme Court on Wednesday.

It claims the four RCMP officers had no reasonable grounds to detain Dziekanski or stun him multiple times with a Taser after being summoned to the airport to deal with an agitated Dzieksanki.

Cisowksi's lawsuit also alleges that RCMP failed to notify of her son's death -- that was left to an airport employee when she returned to the airport to find him -- and then "knowingly misrepresented her son's conduct and the cause of his death."

In the statement of claim, she says she it wasn't until she saw a witness' video of the confrontation her son had with the four RCMP officers that she realized how he had died. Cisowski says she saw the video prior to it being released to the media.

The lawsuit alleges the airport and federal border officers also failed Dziekanski, by not providing translation services or adequately helping Dziekanski, either when he was making his way through customs or after he began throwing furniture in a public area.

These officials also failed to provide Cisowski any "meaningful" assistance, and she left the airport while her son was still waiting inside the customs area.

A Justice Department lawyer confirmed that the federal ministry has been served but no statement of defence has been filed and the department declined to comment Thursday.

With files from CTV British Columbia's Peter Grainger and The Canadian Press