Gerry Adams has denied he was involved in the murder of widow Jean McConville.
The Sinn Fein leader was earlier released from custody after four days of questioning by police in connection with the murder of the mother of ten in 1972.
McConville was wrongly suspected of being an informer and was abducted from her home in front of her children, who were told she had abandoned them. Her body was discovered in 2003 on Louth beach 50 miles from her home.
After being questioned for 96 hours about the abduction and murder of McConville, Mr Adams was freed without charge.
Speaking at a news conference this evening in West Belfast he said: "I am conscious there is another family at the heart of this. That is the family of Jean McConville.
"Let me be very clear, I am innocent of any conspiracy to abduct, kill and bury Jean McConville."
He added: "I rejected all of the allegations made against me."
The son of Mrs McConville vowed to continue the fight for justice for his mother
"The McConville family is going to stay to the bitter end until we get justice," he said.
Mr Adams was arrested on Wednesday and officers were granted a further 48 hours to question him and had until 8pm tonight to charge him or release him.
Mr Adams' arrest has resulted in a political row, prompting Northern Ireland's First Minister Peter Robinson to accuse Sinn Fein of attempting to blackmail police, after the party warned it would review its support for policing if Mr Adams was charged.
Mr Robinson said: "The PSNI must not be the subject of republican bully boy tactics."
Senior Sinn Fein member Gerry Kelly told reporters that the timing of the arrest was political.
"Like myself and all the members of Sinn Fein, he believes that the timing of this was political, that the extension of it was political and he's worried about the damage that it might be doing to the image of policing as well and that it's been mishandled in that type of fashion," he said.
Protesters started to gather as news broke that Mr Adams was to be freed.Earlier, Loyalists blocked roads outside Antrim police station in Northern Ireland in an attempt to stop officers releasing the Sinn Fein leader.
Dozens of protesters holding flags and placards staged a sit-down protest in an attempt to stop officers releasing the Sinn Fein leader.
Mr Adams, left the police station by the back gate in an armoured police vehicle.