Leicestershire Police failed to pass on full information to Derbyshire Constabulary about a troubled woman who was later found dead.
But a personal fitness gadget indicated that Jacqueline Brickell had died before Leicestershire Police received the information in the first place, a coroner has ruled.
A Chesterfield coroners' court inquest heard Ms Brickell - who experienced relationship issues and had a history of mental health problems, self-harm and alcohol addiction - passed away after taking a toxic combination of prescription medication.
Much-loved Ms Brickell, who worked as a nurse, was 56.
The court heard Sandra Knight, of Leicestershire, called police at around 7.30pm on July 22 last year as she was concerned for the safety of her friend Ms Brickell, who lived on Catherine Street, Alfreton.
Leicestershire Police transferred some of the information provided by Ms Knight to Derbyshire Constabulary.
However, Leicestershire Police did not inform Derbyshire Constabulary that Ms Knight said Ms Brickell had previously self-harmed and had previously been admitted to a mental health unit.
Derbyshire officers attended Ms Brickell's home at around 11pm but did not receive a response so decided to return the following morning.
Police went back to her property in the morning, gained entry and found her body.
DC Daniel Saunby, of Derbyshire Constabulary, said police may have forced entry into Ms Brickell's house on the evening of July 22 if Leicestershire Police had provided full details.
He told the inquest: "Not all of the information was passed on to Derbyshire Constabulary to be able to make a full risk assessment and manage the incident properly."
The inquest heard the Independent Police Complaints Commission (IPCC) launched an investigation into Leicestershire Police not giving full details to Derbyshire Constabulary.
Nobody faced criminal action and nobody lost their job as a result.
DC Saunby said four electronic devices belonging to Ms Brickell were examined after her death.
One of the devices was a Fitbit, which was capable of monitoring Ms Brickell's heart rate.
According to DC Saunby, the Fitbit last recorded Ms Brickell's heart rate at 3.45pm on July 22.
But he said: "No tests have been done in terms of accuracy regarding the Fitbit so a time of death can't be confirmed."
However, coroner Peter Nieto said: "On the balance of probabilities, it seems to me likely that Ms Brickell was dead before Ms Knight made the call to police at around 7.30pm on July 22."
Mr Nieto said he could not conclude that Ms Brickell died by suicide.
He explained: "It's clear to me that Ms Brickell took the tablets as a deliberate act - but I can't find that she intended to take her own life.
"She had the option to take more medication but she didn’t - and she didn’t leave a suicide note."
Mr Nieto recorded an open conclusion and offered his condolences to Ms Brickell's loved ones.
Whoever you are, however you feel, whatever life has done to you, please remember that you are not alone and help is at hand. You can call the Samaritans for free on 116 123 or email them jo@Samaritans.org. The Samaritans are there all day, every day.