Cilla Black’s doting son Robert discovered the star’s body after smashing his way into her bedroom when she failed to rise from an afternoon siesta.
The legendary singer and TV presenter’s eldest child broke open her door when he went to see if she was okay late Saturday afternoon and got no response.
Spanish sources said Cilla’s son found her lying on her back on a sun terrace adjoining her bedroom.
She was already dead by the time he found her in the upstairs room of her villa near the Costa del Sol resort of Marbella.
Paramedics arrived at the property in a quiet cul-de-sac around 6pm on Saturday but could do nothing to save her.
Her body was removed around 1.30am on Sunday morning after police, a forensic expert and the judge in charge of a routine investigation into Cilla’s death visited the scene.
Traffic jams in the area caused by a nearby David Guetta concert are understood to have delayed the arrival of some of the officials called to the detached property – called Casa Roll – and led to the agonising wait before Cilla’s body was taken away.
It was driven directly to the Forensic Medicine Institute in Malaga where a post-mortem is expected to take place later today.
Spanish police confirmed yesterday/on Sunday they were awaiting autopsy results but said everything was pointing towards Cilla’s death being the result of “natural causes.”
But sources close to the investigation said this morning medical examiners will look closely at marks on her right arm and elbow which they believe may be linked to a fall potentially caused by a sudden temperature change.
A source close to the inquiry said: “Cilla’s son found her lying face upwards in a solarium-style sun terrace next to her bedroom.
“There’s no conclusive autopsy results yet but the main theory right now is that she had a dizzy turn after going from an air-conditioned room into the midday heat and losing her balance.
“The marks she’s got are consistent with a fall where she’s put up an arm as a defence mechanism.
“What’s need to be determined now is why she fell and whether it was indeed to do with the sudden change in temperature and the effect that had on her – which seems the most likely scenario at the moment – or whether something else triggered the collapse.
“Midday temperatures on Saturday in the area were in the high eighties and we know Cilla wasn’t in the best of health.
“More tests may be necessary after the autopsy to get to the bottom of what’s really happened.
“There’s no evidence to link Cilla’s death to any criminal act but police and courts generally like to keep an open mind on things.
“The possibility she fell because she was confronted on the terrace by a would-be burglar has also been looked at and not yet excluded although it is not being seen as a probable scenario.”
Investigators believe Cilla died at some point between 1.30pm on Saturday when she went upstairs for her afternoon nap – and 3.30pm.
Her eldest son is understood to have jetted to Spain the day before the tragedy.