The 41-year-old was detained in the east of this city on Wednesday morning by detectives carrying out the murder probe.

His arrest brings to 12 the number of people to be arrested in the police investigation into the Short Strand murder last month.

Others arrested included IRA Shankill bomber Sean Kelly and Sinn Fein member Sean Clinton.

Patrick Fitzpatrick was later charged with possession of a firearm with intent to endanger life.

Detective Chief Inspector John McVea said: “The suspect has been taken to the Serious Crime Suite at Antrim Police Station for questioning.”

The PSNI said the murder involved members of the Provisional IRA and a criminal gang called Action Against Drugs (AAD).

The police also said that the Provisional IRA leadership structure remained in place but it was not “on a war footing”.

The crisis has led to the UUP withdrawing its one minister from the Executive amid plans to set up an opposition, saying trust in Sinn Féin has been shattered.

DUP leader Peter Robinson met with Prime Minister David Cameron in London on Tuesday after the DUP leader failed in an attempt to stall the return of the Assembly by four weeks.

The crisis could lead to the suspension of the Assembly for up to up six weeks as fresh talks are called.