Residents have been left in shock after two women died and two others were seriously injured in a suspected stabbing in Milton Keynes on Christmas Day.
A 49-year-old man from the Buckinghamshire city was arrested on suspicion of murder and attempted murder and is in custody, Thames Valley Police said.
Officers were called to a block of apartments in Santa Cruz Avenue, Bletchley, at about 6:30pm on Wednesday.
The women, aged 38 and 24, died at the scene.
A teenage boy and a man in his late 20s were taken to hospital with serious injuries where they are both in a stable condition, police said.
A dog also injured in the incident was taken to a vet but did not survive.
Shazna Muzammil, a Conservative councillor on Milton Keynes City Council, said in a statement on X: “This is horrible on Christmas Day and we are deeply shocked and saddened by the tragic events in Bletchley.
“Our thoughts are with the families, friends, and neighbours of the two women who have tragically lost their lives.”
Ms Muzammil said those involved in the incident were known to each other.
A cordon was in place at the scene throughout Thursday and a forensics team entered and walked up the stairs of a block of flats.
Later, the team took photographs in a room on the top floor of the flat and of sections of road outside.
Numbered yellow evidence markers and first aid kits were on the road and pavement outside, and on the boot of a car parked in adjoining Trinidad Grove.
A family left flowers outside the police cordon.
The group attached two bouquets and a grey teddy bear wearing a Father Christmas outfit to the railings around a children’s play area on Santa Cruz Avenue.
A woman in the group told the PA news agency she did not know the victims and added: “This is a lovely area. You don’t expect to see this kind of thing here.”
The local St Joseph’s church said it would open the school hall from 4pm to 7pm on Sunday, for those seeking “a moment of quiet contemplation or prayer, to light a candle or simply to have a cup of tea and a chat” following the incident.
Senior investigating officer Detective Chief Inspector 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.”
Anyone with information or footage is asked to call 101, quoting reference number 43240622935, or contact Crimestoppers on 0800 555111.