Detectives investigating the murder of Police Constable Ronan Kerr have been questioning a man in Northern Ireland.
The 26-year-old was detained in Scotland on Wednesday after the Police Service of Northern Ireland (PSNI) made one of its most significant arms discoveries for years.
Kalashnikov rifles, rocket launcher components and possible Semtex explosive were discovered in east Tyrone, police said.
The arrest of the man in Dunbartonshire came as the funeral of the Catholic officer on Wednesday heard a plea for an end to violence from Ireland's most senior Catholic churchman, Cardinal Sean Brady, and as huge crowds rallied in Belfast demanding peace.
Pc Kerr, 25, died when a booby-trap bomb exploded under his car in Omagh, County Tyrone, on Saturday. The murder has been blamed on dissident republicans opposed to the peace process and is believed to be aimed at deterring Catholics from joining the police.
Cardinal Brady said: "The people have said no, never again, to the evil and futility of violence."
The weapons seizure was made in a garage on the Mountjoy Road, Coalisland. The haul, found in stolen vehicles, included four rifles, ammunition, timer power units, detonators, incendiary bombs, components for rocket launchers and other explosive devices, and a quantity of explosives, possibly Semtex.
Cardinal Brady said the people rejected those blamed for killing the new recruit, and pleaded with parents not to allow their children to become involved in violence.
PSNI officers and senior Gaelic Athletic Association (GAA) members stood side by side and helped carry Pc Kerr's coffin into the Church of the Immaculate Conception in Beragh, County Tyrone, in an unprecedented sign of unity.
Cardinal Brady told mourners: "The people have said no, never again, to the evil and futility of violence. They have said an emphatic no to the murder and mayhem of the past. Let there be no doubt that the killing of Ronan Kerr was totally unjustified. It was an evil deed, an offence against God and a complete rejection of the belief that human life is sacred."