Both video of the police action and reports from neighbours suggest that multiple shots were heard during the 'entry' ... but "a police spokesperson" has stated that the offender was killed with one only shot
.. Another described "bullets coming through the roof". But police say they fired only one shot.
My quick research suggests that this "distraction device" might be a CO2 powered "grenade" such as those marketed by American Speciality Ammunition Inc . - Valken in USA for around US$50. plus each and shown in this video below: