STONY PLAIN, Alta. - Two RCMP officers on the scene where four Alberta Mounties were shot and killed near Mayerthorpe are to testify today at a fatality inquiry.

Const. Garrett Hoogestraat was outside gunman James Roszko's Quonset hut and heard shots go off the morning of March 3, 2005.

Hoogestraat and fellow officer Steve Vigor encountered Roszko after he ran out of the Quonset.

Vigor shot Roszko, who ran back into the hut, then took his own life.

Cpl. Lorne Adamitz is also expected to testify.

He was at the Roszko property hours before the shooting and helped police seize marijuana plants.

The hearing is being held in Stony Plain, west of Edmonton, to determine if there are any lessons to be learned from the tragedy.