An investigation is expected to be carried out as to how a man detained under the mental health act was able to flee Craigavon Area Hospital shortly before and elderly couple were stabbed to death in their Portadown home.
A 40-year-old man was detained by police shortly after the bodies of devoted couple Michael and Lillian Cawdrey were discovered in their home at Upper Ramone Park.
It is believed an intruder entered the couple's specially adapted 'granny flat' stabbed them both before making off in a stolen car.
A sister and brother-in-law of the couple, both aged 83, raised the alarm and a man hunt was launched. A suspect was arrested following a short stand off with police.
A major incident investigation is now expected to be launched as to how the suspect was able to leave Craigavon Area Hospital unchallenged.
The suspect had been detained earlier yesterday in the Newry area, members of the public had reported man walking around naked and acting erratically.
He was transferred to Craigavon Area Hospital which has a special mental health unit, but it is not yet known how he managed to leave the unit unchallenged.
Police had sought to reassure residents living nearby by releasing a statement confirming a suspect had been arrested and that they were not seeking anyone else in connection with the double murder.
The attack took place in a leafy residential cul-de-sac of Portadown, Ulster Unionist MLA Doug Beattie said people were "visibly shocked" that such an awful tragedy had occured on their doorsteps.
"This is a very quiet area of Portadown which has been visited by an absolutely terrifying situation", he said.
"I welcome the fact that the police have arrested a man and are not looking for anyone else in connection with the incident.
"The family affected and the local community must be given time and space to come to terms with this dreadful tragedy", he added.
DUP councillor Margaret Tinsley, who was one of the first people on scene, said her thoughts were with "the couple's extended family and indeed the entire community who are deeply shocked by this terrible event".
A spokesperson for the Southern Health and Social Care Trust said as the matter was under investigation by police they would not be commenting further at this time.
