The Police Ombudsman is to send a file to the director of public prosecutions this month for him to decide if two former police officers should be prosecuted for a range of crimes, including conspiracy to murder.
The former Special Branch agent handlers were questioned in October about allegations made by a former UVF commander and police informer.
Gary Haggarty agreed to become a supergrass more than five years ago.
A former UVF battalion commander in north Belfast and east Antrim, Haggarty has been charged with 212 offences, including five murders.
He has made allegations of serious criminal activity against his former handlers, as well as members of the UVF.
Police Ombudsman Michael Maguire has told BBC Northern Ireland's Spotlight programme that a file will be sent to Barra McGrory QC "within a matter of weeks".
The programme investigates why, more than five years after he signed a contract to become an assisting offender, Haggarty has still not testified in the witness box.
Spotlight has established that he has now been interviewed by the PSNI almost 1,000 times since August 2009. The process has spanned almost as many years as World War Two.
The families of victims of the UVF in north Belfast said they have had to wait too long to hear what Haggarty has to say about what happened to their loved ones, and those he says were involved.
Their concerns are shared by Baroness Nuala O'Loan, the former Police Ombudsman, who is one of two independent monitors appointed to oversee the investigation on behalf of the families.
"There is a process which has to be gone through and I understand that, but there's a difference between a year, two years and five years - it's too long for the families," she tells the programme.
The senior investigating officer, Det Ch Insp Richard Campbell, said the length of time is entirely reasonable due to the complexity of the case.
"It is one of the largest investigations that the PSNI has ever undertaken," he said.
"It covers very serious criminality, and it covers a large number of people, so it is a massive case."
But victims' families said the police do not want to see Haggarty giving evidence in court because of fears about what he might say about the former Special Branch handlers he reported to while working as an informer for both the RUC and the PSNI.
The accusation is rejected by Det Ch Insp Campbell.
"I spent the last five years determined to make sure that we do get prosecutions as a result of what Gary Haggarty says, so I completely reject any allegation that there's any effort or attempt to deliberately undermine the process - it's just not the case," he said.
The families also speak of their anger at a decision by the PSNI to remove the only four people working full time on the Haggarty case.
The move has also been criticised by Baroness O'Loan.
"I'm astonished, given the nature and complexity of this case, given the history of it," she said.
The PSNI said the four were removed as a result of dwindling resources.
Spotlight: Silence of the Supergrass will be broadcast on BBC One Northern Ireland at 22:45 GMT on Tuesday 3 March