Three of the four men arrested on Tuesday by officers from the Rosemary Nelson murder investigation team have been released.

A report on the three will be submitted to the Director of Public Prosecutions to consider prosecution for possession of articles likely to be of use to terrorists and attempted murder on 10 May this year.

A fourth man has been detained at Lisburn police station for further questioning.

Another 41-year-old man, arrested by officers from the same team on Monday, has been charged with conspiracy to murder.

The charge does not relate to Mrs Nelson's murder.

He is due to appear at Craigavon Magistrate's Court on Wednesday.

He has also been reported to the DPP for consideration of prosecution for a number of serious offences, including directing a terrorist organisation.

The four arrests followed a security operation in the Portadown area on Tuesday.

The men were being questioned about serious crimes not connected with the murder of Lurgan solicitor Mrs Nelson.

The Catholic mother-of-three died in a booby-trap car bomb near her home on 15 March 1999.

Released without charge

A splinter loyalist group, the Red Hand Defenders, said it carried out the murder.

The Red Hand Defenders is a cover name which has been used in the past by the Ulster Defence Association and Loyalist Volunteer Force.

In the past, several people have been held for questioning about the murder, but have been released without charge.

The investigation into Mrs Nelson's death is being carried out by a team headed by Norfolk Deputy Chief Constable Colin Port.

There have been allegations of security force collusion in the killing of the 42-year-old solicitor because of her role as the legal representative for the nationalist Garvaghy Road Residents' Coalition and other high profile cases.

Last August, Mr Port said the investigation had uncovered nothing pointing to security force collusion in the killing.