Published Wednesday, 16 May 2012
A senior UDA member, Mr Coulter was murdered in 2000 during a loyalist feud.
His daughter Tracey said the family gave police permission to keep a piece of his skull, but they have now been told more parts of his body may have been retained.
"It's in black and white that they have something," Tracey told UTV.
The letter, which the family received less than a week before Mr Coulter's birthday, states:
"As a result of a recent audit it has been discovered that in some cases it is possible that the deceased's next of kin was not advised that samples had been retained."
Now we're left asking the question what else have they taken from my daddy? We don't know.
"The way the letter's detailed about 'a family member' - that's my daddy."
Police have apologised for not previously informing relatives, but the Coulter family say that is not enough.
"An apology doesn't even begin to put in words what this has caused for my entire family. It's a disgrace and an outrage.
Police reiterated that keeping body parts for the purposes of police investigation is not illegal, but they acknowledged it is "good practice" to tell relatives what is being kept.
Solicitor Padraig Ó Muirigh said the right of families to be made aware is "paramount".
"This is causing further anguish to these families
"It's remarkable that in this day and age families are being treated in this way - these are families that have been through very traumatic events and are being re-traumatised by the failures of the PSNI.
"There may well be civil proceedings against the Chief Constable," he added.
On Wednesday Prime Minister David Cameron expressed sympathy to those "anguished" by the revelations.
© UTV News