A man has been arrested as part of a garda investigation into the murder of Alan Ryan in Dublin.

Gardaí in Coolock last night arrested a man in his late 40s and he is currently being detained at a garda station in the north of the city.

Ryan, who was from Grange Abbey Drive in Donaghmede, was shot dead on Grange Lodge Avenue in Clongriffin on Monday.

He had served jail terms for IRA activities and gun possession. Detectives believe he had recently been involved in a Real IRA group that was in conflict with a Dublin drugs gang.

Gardaí feared retaliation following the shooting and set up a number of armed checkpoints in Dublin earlier in the week.