Gardaí investigating the murder of Andrew Allen in Buncrana last night say they cannot link the killing to any particular organisation.
The 24-year-old victim, who was a father-of-two, was shot through a window of a house at Links View Park in Lisfannon at around 9.20pm last night.
Andrew Allen was from the ''Top of the Hill'' area of the Waterside in Co Derry.
Gardaí said the focus is on Northern Ireland, but they are keeping an open mind and are liaising closely with the PSNI.
They would not comment on Mr Allen's background and speculation that he had been told to get out of Northern Ireland, but confirmed that he had been living in Buncrana for up to six months with his partner.
She was in the house with him last night when he was shot dead. She was not injured in the incident.
Gardaí say a car with two or possibly three men reversed into the driveway of the house at approx 9.22pm.
They first attempted to get in the front door but failed and then a number of shots were fired through the bedroom window killing Mr Allen.
The car then drove in the direction of Fahan and was found burned out in the townland of Ballyhone.
It was a silver Vauxhall Cavalier with a northern registration - SJI 2117.
Gardaí are appealing to anyone who saw anything suspicious in the Links View Park or Fahan area to contact the incident room in Buncrana Garda Station on 074-9320540.
The State Pathologist arrived at the scene this afternoon.
Sinn Féin condemns attack
Sinn Féin has condemned the murder, which it says has caused shock in the border area.
"There is shock in the community on hearing the news of the murder of this young man in Buncrana,'' said Sinn Féin MLA for Foyle Raymond McCartney.
"His life has now been cut short and a family has now been plunged into grief and despair.
''People north and south have rejected these actions; they need to stop immediately.
"I would appeal to anyone who noticed anything unusual or suspicious before or after the shooting to come forward to gardaí immediately."
Waterside parish priest Fr Michael Canny said it was an act that could not be justified.
The Church of Ireland Bishop of Derry and Raphoe has described the murder as "an outrageous and inhuman act".