The 43-year-old man arrested for questioning about the Real IRA murders of two soldiers at the gates of Massereene army base earlier this year has been released without charge.
He was being questioned about the murders of Sappers Patrick Azimkar, 21, from London, and Mark Quinsey, 23, from Birmingham, who were gunned down in March.
He was also being questioned about the attempted murder of five people in the same gun attack, two of them drivers delivering pizza to a soldier who was about to head off for a six-month tour of duty in Afghanistan.
Leading dissident republican Colin Duffy, 41, from Lurgan, Co Armagh, has already been charged with the murder.
A second man, cystic fibrosis sufferer Brian Shivers, 44, from Magherafelt, Co Londonderry, has also been charged with the killings. He was granted bail because of his condition.
The soldiers were the first to be murdered in Northern Ireland in 12 years, and their deaths were followed two days later by the Continuity IRA murder of Pc Stephen Carroll in Craigavon. He was the first policeman to be murdered in Northern Ireland since 1998.
A 22-year-old man being questioned about the policeman's murder was released on Tuesday pending a report being sent by police to the Public Prosecution Service.
On Saturday, relatives of Patrick Azimkar, and Mark Quinsey wept as their regiment returned to the base from their tour in Afghanistan.
The sister of Mark Quinsey, Jaime, also spoke about her pain at seeing the spot where her brother was gunned down.
© UTV News