Excavations at a cemetery in Taffs Well near Pontypridd have revealed an empty grave which should have contained two coffins.
Excavations have tried to locate Peter Mist's body
It is the latest in a series of mistakes discovered at three cemeteries in Rhondda Cynon Taf.
The empty grave was discovered during a search for the body of Peter Mist.
It was found on Wednesday that another body had been placed in the grave at Ty Rhiw cemetery, where Mr Mist should have been buried alongside his wife.
In the latest irregular burial, cemetery records and surveying equipment had indicated there should have been two coffins in the grave that was being investigated.
After excavating for two hours to a depth of more than one-and-a-half metres, no remains were found in the grave.
Since the investigation began into irregularities at three cemeteries in the Rhondda Cynon Taf area, six graves have been disturbed, involving five different families.
One council worker has been suspended and a police investigation is under way.
The excavation of an adjacent plot to find the coffin of Mr Mist took place on Friday, as his family watched.
Mr Mist's daughter, Helen Mist, said the family had been devastated by the mistakes at the cemetery.
Helen Mist said the mistake had upset her family
"We are very anxious and we are not getting a lot of sleep," she said.
"There are children involved in this - our family are upset.
"My daughter is coming home from school crying over it because she's being questioned - it's unbelievable."
The Mist family solicitor, John Graham, added: "We have had coffins which are in the wrong plots, coffins which are not yet identified.
"And at this point in time, we have coffins which we can't locate."
In a statement, South Wales Police said their inquiry was continuing and that bereavement counsellors were helping the families involved.
The statement said: "South Wales Police are continuing to investigate the criminal allegations concerning discrepancies identified in the mandatory register of burials which are required to be retained by Rhondda Cynon Taff council.
"As part of this investigation, it is necessary to carry out a small number of excavations in the Cefn y Parc, Ty Rhiw, and Glyn Taff cemeteries.
"Those excavations have been carried out with the full co-operation of the families that have been affected, all of whom are being treated in a sensitive and professional manner by both police and local authority representatives.
"CRUSE bereavement are helping with counselling and have been involved from the outset.
"A council employee has been suspended in connection with the investigation and is currently on police bail."
Rhondda Cynon Taf Council and South Wales Police are investigating a series of errors at three cemeteries in the area.
In September it emerged that relatives of a woman who died more than two years ago had held a second funeral for her after she was buried in the wrong grave with a stranger.
Lilly Blackburn died in 2001 and should have been buried in the same grave as her husband, who died in 1959. Instead, she was buried in the next grave along.
On the day of the funeral her daughter Marlene Jones raised her concern that Mrs Blackburn was being buried in the wrong grave.
Funeral directors and council officials were told and the ceremony was held up for 40 minutes while records were checked.
Visiting wrong grave
But the family were told that that they had made a mistake - and that Lilly Blackburn was, in fact, being buried with her husband.
They were told that they had been visiting the wrong grave for more than 40 years, and the ceremony went ahead.
But, after two-and-a half years of campaigning, council officials have confirmed that the family were right all along.
They were spurred on by an earlier irregularity involving another family.
At the time, a spokesman for the council said :"Rhondda Cynon Taf Council is continuing its investigation in conjunction with the South Wales Police into claims of irregularities to entries in the registers of burials in the Taf Ely area.
"The cemeteries involved are Cefn y Parc, Ty Rhiw and Glyntaff."