A retired civilian RCMP firearms expert took the stand Tuesday morning at a fatality inquiry looking into what led to the deaths of four constables on March 3rd, 2005. Bruce Gunn told the court it one of the officers was already down when he fired a shot at Roszko.

Constables Anthony Gordon, Leo Johnston, Brock Myrol and Peter Schiemann were killed by James Roszko on a farm property near Mayerthorpe, before the gunman turned the weapon on himself.

Bruce Gunn told the court it appears Const. Johnston was laying down when he fired a shot at Roszko. He also said Johnston's gun jammed and was unable to fire again.

The court also heard the one shot fired by Johnston hit a gun Roszko had in his waistband.

It was revealed that Roszko had not been injured at that point. Roszko fired on Johnston four more times in total more than any of the other officers.

It was also noted that after Johnston fired at Roszko, the cartridge case did not eject from is gun. It's not known why that happened. The gun was tested following the incident without any problems.

Another officer testified that seven out of eight firearms in Roszko's possession were not registered. The deadly H&K assault rifle Roszko used on the officers was prohibited.

"He did not have any licensing or firearms licence and made no attempts to get a licence or register firearms," said Sgt. Dale Baumgartner.

During Tuesday's testimony, it was mentioned that the assault rifle Roszko used also stopped another bullet, one that had entered Roszko's hand from Cpl. Steve Vigor, a retired member of the RCMP, who exchanged gunfire with Roszko.

Vigor also struck the gunman in the upper leg when he exited the Quonset.

Sgt. Kevin Quail told the court Monday the investigation that followed the shootings of the four officers had police looking for possible associates, weapons and even underground tunnels.

Investigators did end up finding two rifles above one his marijuana grow rooms.

"On top of the grow there was a roof and a piece of plywood on top of that...you lift up the plywood and inside that a guncase with a twenty-two calibre and a shotgun," said Quail.

Quail said he found no indication of any tunnels on the property.

Former RCMP Insp. James Hardy who was the lead investigator in the case also took the stand Monday.

Hardy said one of his first tasks was to find out where Roszko and who he had talked to. His cellphone showed five calls to Shawn Henessey.

Henessey and Dennis Cheeseman were each convicted of four counts of manslaughter in relation to the case. They were denied standing in the fatality inquiry.

Roszko made another five calls to his mother. She told police he wanted her help stashing his pickup. But Hardy said the big question everyone wants answered, likely won't be known.

"I can't say specifically how he got into the Quonset. There's lots of theories out there, but that part there, I'm just not comfortable talking about," said Hardy.

On Wednesday, a bullet path analyst will take the stand at the fatality inquiry.

With files from David Ewasuk