UP to 50 murders allegedly linked to a top British spy within the IRA include other state agents who had "outlived their usefulness", the High Court has heard.
Lawyers for relatives of one victim also claimed the PSNI lack the "appetite" to investigate the activities of the army's prized intelligence asset, operating under the codename Stakeknife.
The allegations were made as a legal bid to have an outside police force carry out the probe was listed for a hearing next year.
Judicial review proceedings have been brought by the family of Caroline Moreland, a 34-year-old Catholic mother-of-three from Belfast, abducted and murdered by the IRA in July 1994 for being an alleged British informer.
Her children are seeking a wide-ranging investigation into the full circumstances surrounding a series of killings stretching back to the 1980s attributed to the IRA's internal security team.
In October, Director of Public Prosecutions Barra McGrory QC called for police to examine Stakeknife's activities, along with what was known by RUC Special Branch and MI5.
Relatives of those allegedly killed by the so-called 'Nutting Squad' are opposed to the PSNI taking charge.
Scappaticci, who denies being the agent, left Northern Ireland in 2003 when he was identified by the media as Stakeknife.
In court yesterday barrister Sean Devine said: "One of the criticisms is the PSNI don't have any appetite for this investigation because it will necessarily involve criticisms of the security forces.
"...The position is that the families of the various deceased, and we are talking in excess of maybe 50 murders have been reported, are awaiting answers for a very long time.
"The core subject matter of this challenge is the use of a state agent to kill, amongst others, other state agents that had outlived their usefulness in the eyes of the authorities.
Counsel for PSNI Chief Constable George Hamilton indicated "a range of options are under consideration" and he "continues" to liaise with "a number of other bodies who may have an interest in the matter".
Mr Justice Maguire listed the application for leave to seek a judicial review for hearing in February.
