The bomb that killed six Canadian soldiers in a LAV-III armoured vehicle was probably both powerful and a lucky strike, says their commanding officer.

"Suffice to say it was a large charge," Lt.-Col. Rob Walker, commander of the Gagetown, N.B.-based Royal Canadian Regiment battle group, said Monday about the Easter Sunday blast in Afghanistan.

But the question now becomes why the bomb managed to kill so many soldiers in a vehicle that has otherwise provided solid protection for Canadian soldiers.

"The LAV is a great vehicle," said Walker, a native of North Battleford, Sask. "But you can always make a bigger bomb. And everything is penetrable."

The remains of the eight-wheeled, 17,000-kilogram vehicle are being returned to Kandahar for further examination.

Coalition officials say because the Taliban can't match NATO firepower, they use guerrilla tactics such as ambushes, suicide bombers -- and roadside bombs.

Ten soldiers were in the vehicle. Four survived the blast, although one man suffered serious injuries. The three who weren't injured -- the driver, commander and gunner -- were up front.

The man in the back who survived got blown out the back of the LAV had first-aid training and remained conscious, CTV's Paul Workman reported from Kandahar.  "He was able to tell his gunner how to stop the bleeding and how to treat his wounds, and that probably saved his life."

Walker didn't know whether Sunday's blast was carefully planned or a lucky shot: "I think it was both, to tell you the truth. It was a big bomb."

The soldiers of Hotel Company were on their way to provide an escort to convoys moving troops and supplies into Helmand province to support Operation Achilles, an offensive targeting the Taliban. They were about 75 kilometres west of Kandahar City in the Maywand district.

Workman said that three LAVs were trying to cross a series of interconnected irrigation canals. The path they found led through a choke point, and that's where the Taliban buried the bomb.

"They thought they had a place wide enough for the LAV to cross, and so they tried, and as they crossed they hit an IED," Walker said.

Military officials think the bomb used a pressure-plate detonator.

Some have speculated that there was extra ammunition in the LAV that detonated after the blast, causing the high death toll.

Walker said there wasn't extra ammo in the vehicle, but no one can say yet if the LAV's standard load of ammunition -- 25 mm cannon rounds and grenades -- contributed to the carnage.

The dead soldiers have been identified:

• Pte. David Greenslade, 20, of Saint John, N.B.;
• Pte. Kevin Vincent Kennedy, 20, of St. Lawrence, Nfld.;
• Sgt. Donald Lucas, 31, of Burton, N.B.;
• Cpl. Brent Poland, 37, of Sarnia, Ont.;
• Cpl. Christopher Paul Stannix (reservist), 24, of Dartmouth, N.S.;
• Cpl. Aaron E. Williams, 23, of Lincoln, N.B.

The military is planning a ramp ceremony to repatriate the dead soldiers' remains back to their loved ones in Canada.

The men had been in the field for a month and were on their last scheduled escort mission before returning to Kandahar for some rest and a refit of their LAV.

Walker said the troops still have faith in the LAV, adding roadside bombs and mines are a fact of life in Afghanistan.

"I don't have to reassure my soldiers one iota," he said. "From time to time we will have casualties, deaths, injuries -- but I have complete faith in the LAV because it does its job."

Military analyst Scott Taylor told CTV Newsnet on Sunday that about 20 LAVs have been destroyed by enemy attacks in Afghanistan. "But very few people were killed, or if they were injured, they were mildly injured because this vehicle protected the soldiers inside."

Soldiers do have confidence in the LAVs, he said. However, "when something like this happens ... obviously the Taliban have stepped up the size of their detonations," he said.

Canadian soldiers are in a cat-and-mouse game: They try to add more armour, and the Taliban build bigger bombs and use different tactics, he said.

Given NATO's efforts to push the Taliban out of parts of Helmand, Taylor suggested the insurgents wanted to show "they've still got some sting in their tail."

With a report from CTV's Paul Workman and files from The Canadian Press