Emma Bradley, aged 34, was found at her address, in Telford, on February 21 by detectives investigating the murder of Lynn McNally.
In a statement Dc Stephen Davies described how he and a colleague arrived at the property, in Grange Road, Ketley Bank, at 4.40pm to speak to Miss Bradley who was a 'potential witness' in the criminal case. They were not expected and were let in by a relative who thought she was asleep.
The officers realised she was not breathing and applied chest compressions in a bid to revive her while phoning for an ambulance, which did not arrive for 30 minutes.
Giving evidence West Midlands Ambulance Service critical care standards manager Simon Taylor said: "There was a failing by the call taker. They should have followed the NHS pathway script rather than asking the police officer if life was extinct at that stage.
"Lessons have been learned and education and training provided to a number of staff.
"They should have offered the officer CPR advice and asked them if they were happy to carry on with CPR. Then at that point the call handler would ask if the person is beyond help."
Mr Taylor told the hearing at Telford & Wrekin Register Office, that as a result two 'resources' that were initially deployed were diverted by the control room despatchers, who thought they were not needed until a second 999 call was made.
He also said the detectives did not get an update message from West Mercia Police control room informing them the paramedics were not coming because their radio was in the car.
"We then arrived at the scene 15 minutes later than we should have. If we had not being stopped we would have got there nine minutes after the first call," Mr Taylor said.
Ms Pagett added that her niece had a history of depression and took prescribed drugs including sertraline, codeine and co-codamol, not illicit drugs.
The cause of death was given as bronchopneumonia, sertraline and opiates.
Shropshire, Telford & Wrekin Coroner John Ellery told the hearing that even if the ambulance had arrived sooner that it was unlikely she would have survived due to the lack of oxygen to the brain.
He recorded a narrative conclusion that Miss Bradley died from 'natural causes associated with with prescribed sertraline and opiate use'.
"I would also like to record my thanks to Mr Taylor for his investigation. Lessons have been learned. The officers were faced with something wholly unexpected. They were there for a criminal investigation and were faced with a medical emergency.
"I do believe that Emma died at Grange Road. At 6.45pm the hospital staff finally said 'we can't bring her back'. I offer you my condolences," he told the family.