Within hours police had ruled it a suicide.

Part II: Experts claim key evidence missed in doctor’s death as police investigation is questioned

Part III: Haunting clue in suicide note

Part IV: The unsigned will that sparked a bitter war over beach town millions

Part V: Mystery of 2.45am vanishing act inside dead mum’s home

But a six-month investigation by the Sunday Mail has uncovered major inconsistencies in the evidence, casting doubt over what happened to the loving mother of two.

Dr Mahlo was found at her Moffat Beach home with a 25cm chef’s knife stuck in her chest, with two suicide notes printed from her home computer nearby.

A USB plugged into her computer, minutes before the suicide notes were created, disappeared from the home.

Years later investigators established her ex-partner, John Hehir, had used it in his own computer months after her death.

WATCH CHAPTER ONE OF THE MINI DOCO BELOW

The Sunday Mail has pored over hundreds of pages of evidence, tracked down experts in forensics and pathology to review the case and spoke to her grieving family who don’t believe she took her own life.

Dr Mahlo’s family and experts argue an inquest into her death should be reopened, forcing police to reinvestigate, with the original finding of suicide set aside, arguing there is not enough proof she took her own life.

“There are just so many parts of the story that don’t make sense,” her daughter Anastasia Sasonow said.

“Everything screams foul play.”

Detectives handed the case back to uniformed officers within hours of her death.

No body core temperature was recorded at the scene; there was no evidence provided of death scene mapping, scrapings for DNA analysis from Dr Mahlo’s fingernails and testing for blood around the home, such as around taps or sinks.

The knife found in Dr Mahlo’s chest was not examined for prints until five days after her body was found; no DNA was detected on the knife and no tape lifts for DNA were conducted on other items around the bed.

The computer, bedspread and linen were not seized and, while a scenes of crime officer took photos and inspected blood stains, a scientific officer conducting a bloodstain analysis was later unable to classify the bloodstains, or what objects made them.

Police that day wrote a report saying they believed she took her own life, before an autopsy was conducted, or before the chef’s knife was forensically examined.

Dr Mahlo, 52, was found in her bed at her Moffat Beach home on Queensland’s Sunshine Coast by Mr Hehir just after 5am.

The pair had met only two years earlier after he provided her financial advice, and he left his wife and kids to move in with Dr Mahlo.

Mr Hehir and Dr Mahlo eventually broke up.

The prominent doctor who had risen in the ranks had battled bouts of depression and was stood down from her role as executive director of medical services at Nambour Hospital, around the same time their relationship began.

Dr Mahlo was being treated for depression and had been hospitalised in the past following a suicide attempt. She had also previously cut herself.

Police called to Dr Mahlo’s home after her death on May 28, 2008, were told about her previous self-harm attempts, of her depression and excessive drinking, and that she had been seeing a psychiatrist.

After seeing no signs of a struggle – and what appeared an obvious suicide at the time – police held the property as a crime scene for less than seven hours.

An autopsy found Dr Mahlo had an alcohol level of .114 and therapeutic levels of sedative diazepam and the antidepressant citalopram.

No one has ever been charged in relation to the death of Dr Mahlo and police have never identified a suspect.

But issues surrounding the police investigation, and new information that has come to light since her death, has led to forensic experts raising doubt there is enough proof Dr Mahlo took her own life.

THE PHONE CALL

On the morning she was found, Dr Mahlo’s phone called Mr Hehir’s phone at 3.06am, but the call went to a message bank.

Mr Hehir told police he woke up about 4.30am, at his newly rented home at Cotton Tree, saw the missed call and made multiple attempts to reach his ex-partner over the phone.

The pair had argued the day before outside her house. Dr Mahlo told family she was relieved to have Mr Hehir out of her life, after signing over a jointly owned motorcycle to him.

He told police he drove to Dr Mahlo’s house on the morning he found her dead, worried about her after a previous pill overdose suicide attempt on April 11 where she was flown to Brisbane for emergency care.

He said the doors were open to the home and he found her upstairs in her room about 5am, with police coming within about half an hour.

While expressing concerns over other parts of his testimony, the coroner found phone tower location records backed up Mr Hehir’s account of his movements that morning, while he drove to her home.

When police arrived they found two unsigned suicide notes printed from the computer, one of which was to her two children Anastasia and Ben. The other was addressed to Mr Hehir asking him to look after the children when needed.

Within three-and-a-half hours Dr Mahlo’s body was moved to the morgue and by the end of the day police paperwork was completed, appearing to write the death off as a suicide, before an autopsy.

It later emerged that Mr Hehir, who had moved out of the Moffat Beach home weeks earlier, went back inside her home that same day after police dropped him off.

THE USB

It was also revealed a USB was plugged into Dr Mahlo’s computer at 2.45am, about two hours before she was found dead.

Minutes later, two suicide notes were written and printed.

The USB was titled “John’s USB” and disappeared from the home.

Years later a coronial investigation would confirm “John’s USB” with the same serial number was plugged into Mr Hehir’s own computer after her death.

At the inquest an expert said he didn’t know if he had been asked to see when the USB was removed from Dr Mahlo’s computer and no time has ever been provided.

The USB has never been found and its contents were never confirmed.

THE KNIFE

The knife found in Dr Mahlo’s chest wasn’t tested for fingerprints until five days after she was found dead.

The knife didn’t have a hilt, and cuts to her right hand were originally thought to be from the knife when she stabbed herself.

However Dr Mahlo was left-handed, with her family adamant she only handled knives with her left hand, with an alternative theory about her injuries not explored at the inquest.

There were three wound tracks, or stabs, in the single wound in her body, with the first requiring “severe” force.

The coroner found the wound tracks was consistent with Dr Mahlo making some initial attempts at the stabbing.

THE WILL

While its connection to the circumstances of her death, if any, has not been established, days after her death it became clear there would be a dispute between a number of parties over Dr Mahlo’s will.

The doctor signed a will prepared by Mr Hehir in February 2008, which made him the principal beneficiary of her multimillion-dollar estate, some 16 months into their relationship.

The will included a life insurance policy of $1.3m, superannuation of $450,000, a house at Moffat Beach and investment properties.

But after they separated, Dr Mahlo drafted a new will in May, removing Mr Hehir from it. Despite her father saying he saw a printed version, the only version ever found was an unsigned one on her computer.

The details of her wills were examined in a legal dispute over her estate.

The family lost the case and later settled with Mr Hehir.

CONFLICTING ACCOUNTS

During the Supreme Court matter, Mr Hehir initially said he did not go back through the house and his legal counsel said he didn’t step inside.

During a subsequent police interview, in January 2011, he again said he did not go back inside the house. He also denied taking the USB and said it belonged to Karen.

At the inquest in 2014, he said police had given him permission to go inside, also agreeing he must have taken the USB if it had his name on it.

PSYCHIATRIST

A police report written on the day of her death, which was filed in court, said her treating psychiatrist Dr Clive Fraser had said she had two previous suicide attempts, one in which she cut her wrists and nearly bled to death.

The other attempt written in the report said she sliced a large artery in her ankle.

Giving evidence at the inquest Dr Fraser remarked that “they were both very superficial lacerations” that did not require stitches.

The inquest was also told Dr Fraser had concerns about Dr Mahlo’s injuries after she was found dead and wrote to police twice.

EXPERTS

Examining aspects of her death, forensic psychiatrist Dr Russ Scott and forensic pathologist Dr Allan Cala have raised serious concerns about an inquest that in 2014 ruled Dr Mahlo’s death a suicide.

Apart from a lack of police forensic work, and evidence they say does not satisfy a ruling of suicide, the experts have also raised:

*the highly unusual method of suicide, with the most common by medical practitioners and women generally being deliberate overdose

*that she would use a hiltless knife to stab herself through her clothing into her chest

*a medical practitioner would know that a horizontal stab wound between the ribs, over the heart, would be the most effective method of suicide by self-stabbing.

*she was intoxicated and had therapeutic amounts of her medication in her body

*the chest wound had three tracks (suggesting the knife had been manipulated twice), with the first track needing “severe force” to go through the sternum

*Dr Mahlo was left-handed so the injuries to her right hand palm and thumb were “more likely” to be defensive wounds. A police and pathology perspective that her right-hand injuries were from stabbing herself were “inconsistent” with being left-handed.

*an abrasion to her chin, submucosal bleeding on the lips and the bruising to the back of the left hand and right thigh were also consistent with a struggle, which was not explored

Dr Scott and Dr Calla argued the lack of police work raised questions if a suicide ruling was “reasonably supported by the evidence and whether, in the interests of justice, another inquest into the death of Dr Karen Mahlo should be held.”

The Sunday Mail made multiple attempts to speak with Mr Hehir about calls for the inquest to be reopened however he declined to comment when contacted.

The Queensland Police Service was asked if any CCTV footage from homes or traffic cameras was collected to confirm versions; whether any other crime scenes were considered; whether Mr Hehir underwent any forensic tests or whether they seized any of his possessions; where DNA tape lifts were conducted in the home and bedroom; whether her fingernails were scraped for DNA at the scene; whether there was testing for blood in any parts of the house such as sinks; and whether any consideration was given to Dr Mahlo being left-handed.

The Service was also asked if it believed Dr Mahlo’s death was sufficiently investigated on day one; if the homicide squad was ever engaged; at what point investigating officers reached the conclusions it was a suicide; if the investigation carried out by detectives was reviewed by a senior officer and the reasons for concluding a suicide; and if there was any current consideration to a cold case review of the matter.

Despite the criticisms from forensic experts, a spokeswoman said when police arrived officers secured the scene, conducted a forensic examination and carried out an “investigative search of the premises”. The spokeswoman said a thorough coronial report was submitted.

“While the original lead investigator has since retired, a currently serving investigator involved in the initial investigation remained engaged with the matter throughout and provided evidence at the inquest,” the spokeswoman said.

“On 28 May 2008, officers attended the address where a woman was located deceased inside the residence.

“The informant was present on arrival and was treated as a person of interest.

“A forensic examination of the room identified no signs of a struggle. A Scenes of Crime photographer took a series of images of the deceased and a police scientific officer conducted a blood stain analysis.”

Police said they doorknocked and looked at phone records and triangulations conducted for when calls were made on phones.

“Notwithstanding the Coroners’ findings, the Queensland Police Service will investigate any new, credible, reliable and admissible information in relation to this matter,” the spokeswoman said.

The office of the State Coroner Terry Ryan was contacted in relation to the experts’ report and after a request for the coronial finding to be set aside.

“The State Coroner is aware of the issues raised in the article which relates to the death of Dr Karen Mahlo,” a spokesman said earlier this year.

“We can confirm His Honour has received an application to set aside the inquest findings, which requires a substantial amount of material to be reviewed to enable a determination to be made regarding this application.

“No further information can be provided at this time.”