The residents did not have a confrontation with the male and female suspects inside.
Ayliffe said a K9 unit responded and called in the police tactical team based on their observations at the scene.
Sounds of distress were heard from inside the home, prompting the tactical unit to move in.
At 12:15 p.m., Ayliffe said a tactical team member deployed an Arwen less-lethal impact launcher that struck a man. After the launcher was deployed, circumstances occurred which required police to engage with the woman.
“A second tactical member discharged his service firearm. The woman was pronounced deceased at the scene,” said Ayliffe, who added that the man was taken to Foothills hospital in “very serious” condition with stab wounds.
Police recovered a knife at the scene.
It is not known how the man received the stab wounds, and police don’t believe the man or woman have any relationship with the Penbrooke home or homeowners.
Members of the tactical team who deployed their less-lethal and lethal firearms are both constables — one a 12-year-member and the other a seven-year-member of the service.
The Alberta Serious Incident Response Team has been called in to investigate the shooting.
At the time of the incident, Jessie Wallace was picking up a friend next door to where the incident occurred.