Police in the North suspect current members of the Provisional IRA of involvement in the murder of a father-of-nine in Belfast.
Detectives have said they are not in a position to assess whether the killing of former IRA member Kevin McGuigan was ordered by a command structure within the outlawed and supposedly defunct organisation.
Mr McGuigan was gunned down in east Belfast in a suspected feud between former IRA members last week.
Organisational involvement of the PIRA, if proved, would have major significance for the political process in the North. It is almost 20 years since the group called a ceasefire.
Police Service of Northern Ireland Detective Superintendent Kevin Geddes said: “A major line of enquiry for this investigation is that members of the Provisional IRA were involved in this murder.”