A police officer found the dead body of a woman, allegedly killed by her sister and daughter, but was told she was "just asleep".
PC Ryan McIntyre made the discovery after calling at the home of Sharon Greenop, 46, in Troon, South Ayrshire in November 2016.
The officer told the High Court in Glasgow he remembered the "smell of death".
Lynette Greenop, 40, and 20-year-old Shayla Greenop deny murder.
PC McIntyre and a colleague went on to speak with Sharon's sister Lynnette.
A jury heard she appeared "perfectly calm" at one stage and seemed to refuse to accept the death.
It is claimed Sharon was assaulted on various occasions between 8 September and 10 November 2016.
The court earlier heard how Sharon's next door neighbour had gone to police after finding a pungent smell in his own house.
PC McIntyre was one officers who turned up at Sharon's home on 10 November.
The officer said he initially spotted candles burning after Lynette let him in.
The officers went upstairs and entered a bedroom where he first found a "fresh white bread sandwich" near a bed.
But, the constable went on to discover a corpse "covered neck to toe in a white bed sheet".
PC McIntyre said: "There was a strong odour which I can only describe as the smell of death."
The officer - who had only been in the job 10 months - remembered his colleague patting him on the shoulder before they went to speak to Lynnette.
She was initially said to be "perfectly calm" and "not expressing any concern".
PC McIntyre went on: "My colleague asked what had happened up there.
"Lynnette replied: 'What do you mean?' She appeared genuinely inquisitive.
"My colleague said: 'Your sister is dead'.
"She replied: 'She is not dead. She is just sleeping'.
"My colleague stated she had been dead a long time.
"Lynnette then began crying, entered a state of disbelief and was almost refusing to accept what we had saw."
Lynnette was taken into a police van while moves were made to make the house a crime scene.
She claimed she had last spoken to Sharon two days earlier and had "heard her moving about".
But, PC McIntyre said: "I thought at the time this could not be true and Lynnette was disassociating herself from her sister's death."
The officer added Lynnette went on to become "significantly calmer".
This included her chatting about her niece Shayla and what bands they liked.
Her QC Frances McMenamin later asked the officer: "Given what you found in the room and Lynnette's reaction, the whole scenario was utterly bizarre?"
He replied: "That is fair to say."
The trial heard how Lynnette Greenoop ended up "ranting and raving" in her local shop after news of Sharon's death spread.
A worker there had offered Lynnette her condolences, but she was said to have sworn and insisted that "rumours" her sister had been dead for months were lies.
It was alleged Lynnette Greenop claimed those in the shop were responsible for what was being said, and that it "better stop".
A carer who once helped look after Sharon said she was "a perfectly nice person".
The 35-year-old witness said Sharon also "doted" on her daughter Shayla.
The murder charge alleges Sharon was repeatedly struck with "object or objects" and had her neck compressed.
It is said injuries were also inflicted "by means unknown" and that there was a failure to obtain medical help.
Sharon is stated to have been so severely hurt that she died.
The two accused, who both live in Ayr, South Ayrshire, deny all charges.
The trial, before Lady Carmichael, continues.