A mother and son have been found dead at a house in Oxfordshire with the woman's ex-partner suspected of their murders, police have said.
Police said injuries were consistent with a blunt trauma, but could not confirm reports an axe had been used.
Officers found the bodies in Mold Crescent, Banbury, at 0645 GMT and a 45-year-old man was later arrested in Swindon on suspicion of murder.
The woman's two daughters fled the house, one with serious injuries.
The elder of the two, in her late teens, was taken to hospital while the other, aged 13, was unharmed but "extremely traumatised".
'Not random attacks'
Det Insp Steve Duffy said: "As you can appreciate officers went to the address and were faced with a horrific scene.
"There were two people obviously dead or very close to death at the scene.
"All I can confirm is their injuries are consistent with blunt trauma and I can't say if an axe was used but a firearm was not used.
"The police traced a suspect to an address in Wiltshire and police went to that address and effected an arrest."
The policeman said there was a "background" to the deaths and they were not random attacks.
He added: "At this stage we can not confirm the exact nature of the injuries the man and woman sustained, but we can confirm that some kind of weapon was used during the attack.
"At this stage it has yet to be recovered."
More than 40 police officers were working on the investigation this afternoon.
The dead woman was aged in her 40s and her son was in his 20s, police said.
The end-terrace house was cordoned off, and a long stretch of the road was closed to traffic and pedestrians in both directions.
Police officers were also present at a second house in Mold Crescent, opposite the scene of the attack, which officers believe the suspect may have visited during the course of the attack.