A man has died after police fired gun shots at a property where another man was found dead and a child seriously injured.
Police said officers were called to an address in Denmead, Milton Keynes at about 9.40am on Saturday and made a forced entry after acting on information from a witness.
Inside the property, they found a man in his 30s who was later confirmed dead, as well as the child who had serious injuries.
They also located a man in his 20s, with the force saying it understood officers used a Taser before shots were fired at the man.
The man subsequently required first aid and treatment from ambulance crews but was pronounced dead at the scene, Thames Valley Police said.
The young child was taken to hospital.
Police said the dead men's next of kin had been notified and officers were likely to remain on watch outside the property for several days.
The Independent Office for Police Conduct (IOPC) confirmed it had received a referral from TVP and said its investigation was "at a very early stage and no further information can be provided at this time".
Police described the incident as "absolutely tragic" and said their thoughts are with those who had been affected.
"Our thoughts are with all those affected by this tragic incident," the IOPC statement added.
TVP assistant chief constable Christian Bunt, said: "What has happened this morning can only be described as absolutely tragic and will no doubt have an impact on the community.
"Our thoughts are with those who have been impacted by this incident.
"Our major crime unit are working closely with the IOPC to understand exactly what has happened.
"At this stage no one else is being sought in relation to this investigation and we are seeking to support everyone involved.
"Members of the community will see an increased police presence. We would ask anyone who has any concerns or information to please speak to one of our uniformed officers.
Members of the public who have information are asked to call 101.
