On Tuesday, a court in the city heard that Thomas O'Hare, 33, and his 21-year-old girlfriend Lisa McClatchey were attacked by a gang of men who entered their home in Foley Road near Keady in November 2006.
The men poured petrol on the victims and their house before setting them on fire.
Last month Gardaí arrested 40-year-old Martin Smith in Dundalk, Co Louth, while his brother, Niall Smith, 37, from Mourneview in Armagh was detained in Balbriggan, Co Dublin.
The pair were extradited to Northern Ireland where they were arrested and charged with two counts of murder and one of arson.
The Smith brothers showed little reaction to the charges and no applications for bail were made.
They have been remanded in custody to appear again via videolink next month.