The shocking murder of two Portadown pensioners yesterday has been described by a senior detective as "particularly violent".
Detective Superintendent Kevin Geddes also made an appeal to the public for help tracking the movements of a van which police believe was used as the getaway vehicle as he spoke to the media just hours after the brutal murders were discovered.
He said a 40-year-old man has been arrested in connection with the double killing of the 83-year-olds at Upper Ramone Park.
It is thought the attacker used a grey Renault Kangoo Van - registration NJZ 6101 - to flee the scene.
The vehicle belonged to the couple who were murdered. It was found in the Edenderry area, about a mile from the murder scene towards the town centre, at around 5pm.
The suspect - who last night remained in custody being quizzed by police - was arrested near the Springfields housing development off the Gilford Road.
Extra police patrols have been planned for the Portadown area to reassure local residents.
Det Supt Geddes revealed that there had been a break-in at the pensioners home at around 12.20pm yesterday.
It is understood that the double murder may have started off as an "attempted burglary", however police last night would not confirm this.
The names of the couple had also last night not been officially released, but the couple has been named locally as pensioners Michael and Lilian Cawdery.
"Police were called to an address in the Upper Ramone Park area of the town at around 3.40pm this afternoon. On arrival, officers found the bodies of an elderly man and woman in the house," he said. "We are treating their deaths as murder."
The senior detective was asked to comment on speculation that a man had absconded from the Bluestone Unit of Craigavon Hospital - close to the murder scene - yesterday afternoon. But the officer responded that it was "too early to comment" on that.
Last night a spokeswoman for Craigavon Hospital said it would not be commenting on the matter due to an ongoing police investigation, and referred queries to the PSNI.
Det Supt Geddes said: "I can only say that the man has been arrested on suspicion of murder and the PSNI is following a definite line of inquiry."
He added the suspect was arrested under the Police and Criminal Evidence Act, and not detained under mental health legislation.
"I would reassure the public that we now have one person in custody and we will have extra police patrols in the Portadown area," he said. "Anyone with information should contact police on the non-emergency number 101."