Officially, gardaí say the “possibility of a link between the two incidents is a line of enquiry” but it is understood that a murder-suicide has not been ruled out.
The deceased were named locally as Jim and Marie Quigley from Rathmore, Hackballscross, Co Louth.
Mrs Quigley’s body was found by one of her sons in a bedroom of the family home at about 3.45pm yesterday.
The garda investigation into her death is being conducted as a de facto murder investigation, although it cannot be officially upgraded to that until after the autopsy.
It is understood she had suffered severe head injuries. Her body was removed from the scene last night and the autopsy will be carried out today by the State pathologist.
Approximately two hours before Mrs Quigley’s body was discovered in what is believed to have been a locked bedroom, her husband Jim was killed when his car went the wrong way up the M1 motorway near Dunleer, some 50km away.
The car collided with another car and a lorry, resulting in three people being brought to hospital with non life-threatening injuries.
The tragic nature of the deaths has left the Rathmore community and their extended families deeply shocked.
Parish priest Fr Gerry Campbell said: “This is a rural community and a rural parish and it is very close knit and very supportive.
“The whole community is obviously affected by this.”
The circumstances of their deaths “is horrific and we are numb with the devastation. It is surreal.”
Fr Campbell said the reality of what had happened had not hit home and “it will take some time, even after the funerals it will linger”.
“Our hearts and prayers go out to the family of Jim and Marie Quigley and their four children.”
Garda Superintendent Gerry Curley, Dundalk, said gardaí are investigating the violent death of a woman and a forensic examination by the technical bureau was taking place at the house.
An incident room has been set up at Dundalk Garda Station and he appealed for anyone with any information in relation to the matter to contact Dundalk gardaí.
He said there was also an investigation into the fatal accident on the motorway and “the possibility of a link between the two incidents is a line of enquiry”.
“It is the early stages of the investigation so we are keeping an open mind and ensuring we cover all aspects,” he said.
Louth councillor Declan Breathnach said: “This is a terrible tragedy and a terrible loss to the community. My thoughts are with the family and also with those injured in the accident.”