On the evening of April 15, 2012, Const. Jeff Blair had been pursuing a vehicle that was travelling nearly 70 km/h over the posted speed limit on Allen Road.
The pursuit was called off, but Blair later located Lumanglas on Northmount Avenue.
Lumanglas and Blair walked back to the police cruiser.
It was after that point that Lumanglas stabbed Blair in the arms and neck.
According to what Ontario's Special Investigations Unit has reported, Blair backed away from Lumanglas after the stabbing, drew his weapon and ordered him not to move.
But Lumanglas advanced on Blair, which is when the officer fired a series of shots.
The 38-year-old Lumanglas died in hospital five days later.
The SIU cleared Blair about three months after the shooting.
The pending inquest is scheduled to begin on May 12. It is expected to last two weeks and hear testimony from 15 witnesses.
The inquest jury will be tasked with making recommendations to prevent similar deaths in future.