A Belfast city councillor and former Deputy Lord Mayor has been charged with hate speech over a remark she made on Facebook which supported a  loyalist massacre of senior Sinn Fein politicians.

Democratic Unionist Party member Ruth Patterson, 57, was quizzed by police in Northern Ireland after making an online comment which suggested she supported the notion of a fictional terrorist attack on an upcoming republican parade.

Patterson left the police station at around 10.20pm and was cheered by supporters. She is due to appear before Belfast Magistrates' Court on Thursday 22 August.

A controversial web page, which has since been removed, painted a bloody scenario in which paramilitaries would attack the Tyrone IRA Volunteers Commemoration on Sunday Aug 11.

It also named Sinn Fein party president Gerry Adams and Deputy First Minister Martin McGuinness among the so-called ‘fatalities’.

In her contribution to the inflammatory online conversation, Patterson, a former Belfast deputy mayor, said: “We would have done a great service to Northern Ireland and the world getting rid of these evil, devious, scum like individuals.”

After the comment came to light, Patterson issued an apology, stating: she had suffered a “lapse of judgement,” before adding, “I completely withdraw this flawed Facebook morning.”

She also admitted her comment was completely incompatible with what was expected of her as an elected representative and said: “Murder and terrorism can never be justified in any circumstances.”

However, more drama followed Saturday morning when Patterson was detained by the Public Order Enquiry team over “grossly offensive communications” and other serious criminal offences. It is understood the offences are linked to intimidation and encouraging criminal acts.

The DUP criticised Patterson’s comment as “completely unacceptable” in a statement and announced it would be looking into the issue.

However, the party then issued a second statement criticising the PSNI for conducting a “sensationalist arrest” and confirming that they would be raising the matter with police chiefs.

In response to the DUP statement, a Sinn Fein spokesman said: “It’s ironic that a party who claim to be a party of law and order are criticising the PSNI for conducting an investigation.”