Two women have died and a teenage boy and a man have been seriously injured in a suspected stabbing at a block of flats.
They were found by police following an incident in Santa Cruz Avenue, Bletchley, in Milton Keynes at about 18:36 GMT on Christmas Day.
The women, aged 38 and 24, died at the scene while the man, in his late 20s, and the boy were taken to hospital, where they are said to be in a stable condition.
A 49-year-old man from Milton Keynes was arrested on suspicion of murder and attempted murder, and remained in police custody.
Thames Valley Police said a dog was also injured in the incident and was taken to a vet but did not survive.
Det Ch Insp Stuart Brangwin, of the major crime unit, said: “Firstly I would like to extend my deepest condolences to the families of the women who have tragically died in this shocking incident.
“We have launched a double murder investigation, which may be concerning to the wider public; however, we have made an arrest and are not looking for anyone else in connection with this incident and the parties are known to each other.
“Members of the public will see a large police presence in the area while our investigation takes place. If you have any questions or concerns, please feel free to approach our officers and they will do their best to help.”
