A man seen carrying petrol and a firearm before barricading himself inside a Bedford house was shot dead by police after a tense standoff.
Investigators from the Independent Office for Police Conduct (IOPC) were sent to the scene immediately after the shooting on Tuesday, and have officially opened an investigation into the incident.
Bedfordshire Police said officers were called to reports of vehicles being damaged in Aylesbury Road, shortly after 10.40pm on Monday.
A 41-year-old man was found 'barricaded' inside a property and 'making threats'.
Specialist armed officers and police negotiators tried to engage with the man over a 'number of hours', the force said.
Shortly after 6am on Tuesday, police began evacuating neighbours after the man was seen pouring petrol out a window and gas could be smelt.
The police watchdog said that the man was seen presenting a firearm from a window of the property during the incident, which led firearms officers to return to the scene.
Shortly after 9.30am, the man was shot inside the property by armed officers who were outside the address, the IOPC said.
Specialist armed officers and police negotiators tried to engage with the man over a 'number of hours'
The man was declared dead shortly before 10.30am on Tuesday, and a non-police issue firearm was found inside the property, the watchdog has said
The man was declared dead shortly before 10.30am, and a non-police issue firearm was found inside the property, the watchdog has said.
IOPC director Emily Barry said: 'Our thoughts and sympathies are with the man's family and friends and everyone impacted by this incident, including the local Bedford community.
'We have met with the man's family to explain our role and they will be kept updated as our investigation progresses.
'Fatal police shootings are fortunately rare, however when they do occur, it's essential for public confidence that an independent investigation is carried out to establish the full circumstances.
'Our investigation is in its early stages, but we are working quickly to obtain and review evidence as we investigate the actions and decision-making of the officers involved.'
The IOPC said that one shot was fired from a police rifle and two baton rounds were fired, with one having been discharged earlier in the incident.
As part of their inquiries, the investigators are obtaining and reviewing police footage including body-worn video, drone footage and vehicle footage.
The identity of the 41-year-old has not yet been formally confirmed.