A 19-year-old man has appeared in court charged with the murder of Gerry Marron in Carrickmacross almost three years ago.
Aaron McDonagh, of no fixed abode, was arrested at Dundalk train station last night in relation to the Garda investigation.
A special sitting of Monaghan District Court this evening heard he asked "what murder?" when he was arrested by gardaí.
He was subsequently charged with murder and arson by gardaí.
61-year-old Gerry Marron died in a fire at his home in Macartan's Villas in Carrickmacross on March 21, 2016.
Gardaí upgraded their investigation to one of murder after it became apparent the fire was started deliberately.
Mr McDonagh has been remanded in custody to appear in Cloverhill District Court on Thursday.