Relatives of those killed in a notorious loyalist mass shooting said they were suffering "daily torture" due to delays in publishing an investigation.
Five people were killed in February 1992 when UFF terrorists opened fire on the Sean Graham bookmakers shop on the lower Ormeau Road in Belfast.
Too many loved ones have died without knowing the truth, the son of one of the victims awaiting a Police Ombudsman report said on the anniversary of the killings.
Billy McManus, son of Willie McManus, said: "What they're putting us through mentally equates to a form of daily torture.
"People are dying without any form of truth or redress as delay after delay occurs."
Former Ombudsman Michael Maguire has found that "significant, sensitive information" about the atrocity was not made available to his investigators.
A legal challenge by retired RUC officers after the ex-Ombudsman found collusion in the 1994 Loughinisland attack which left six people dead has also held up publication of reports, pending its outcome.
The families and survivors of the bookmakers massacre added: "Certain actions in the courts, in our view, are also designed to thwart attempts at getting to the truth."
No one has been convicted over the killings.
The families of the victims have previously said they believe there was collusion between the killers and security forces in the betting shop shootings.
Maria Sykes, sister of victim Peter Magee, said: "We need this report to find out exactly what happened. It's the not knowing that eats away at you every day and adds to the overall trauma.
"We need this report in terms of healing, recovery and moving on as best we can - repairing our lives."
Helen Duffin, widow of victim Jack, is aged in her 90s, and Roseleen McManus, widow of victim Willie, is 80.
Families are concerned that if delays continue then they might not see the publication of the long-awaited report.
Solicitor Niall Murphy said: "The legal challenge has meant that significant reports by the Ombudsman into just fewer than 40 murders have been held up pending the outcome of the challenge. And it is this delay that affects families awaiting the outcome of reports into the murders of their loved ones.
"I share their frustrations about continuous delay."
Operation Achilles is the name given to the Police Ombudsman investigation into the Ormeau Road atrocity and it includes six additional murders by the same UFF gang during the 1990s in south Belfast in which collusion is also a key feature, families said.
Jim Clinton, whose wife Theresa was murdered in April 1994, a crime included in Operation Achilles, said: "It's galling when you think that the very organisation under scrutiny as part of the Ombudsman's investigation into the murders of our loved ones is the very same organisation taking these challenges and causing further harm to families.
"We can't help but feel this is deliberate and designed as a stalling tactic."