A stalking complaint was made and a bag of weapons was discovered before Gracie Spinks died.
Two police officers have been served with misconduct notices over their handling of a stalking complaint made by a woman who was stabbed to death.
Gracie Spinks, 23, was found fatally injured in a field in Duckmanton, Derbyshire, in June.
It is believed she was killed by Michael Sellers, 35, who she had told police in February was stalking her.
Three other officers are being investigated over a bag of weapons found near the field a month before.
The Independent Office for Police Conduct (IOPC) opened its investigation shortly after Ms Spinks’s death on 18 June.
An inquest held the same month heard she died from a stab wound to the neck in the field, where she had gone to look after her horse.
Friends said she was being stalked by Mr Sellers, a work colleague, who was found dead nearby a short time later.
The IOPC said: “Our investigation is considering whether the force carried out all its safeguarding obligations to Ms Spinks and whether its investigation into the stalking matter was carried out in accordance with relevant police guidelines and policies.
“We are also looking into the actions and decision making of police following the discovery of a bag, containing a hammer, an axe and some knives, in May this year.
“The bag had been found close to where Ms Spinks died several weeks later, and its discovery was reported to the force.”
The IOPC said based on evidence it had seen so far, it had served misconduct notices on a police sergeant and constable over their handling of the stalking and harassment allegation.
Another police sergeant was served with a gross misconduct notice, and two other constables were given misconduct notices, over the handling of the bag.
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