Assistant Norfolk coroner Johanna Thompson told the Norwich inquest: “There’s simply insufficient evidence for me to reach a conclusion.”
She added that conclusions of death by suicide or accident would be “inappropriate” in Dack’s case.
The inquest heard Dack had seen an ex-boyfriend, Kallem Howard, in the hours before she was reported missing, and that she had sent messages to her best friend, Emma Halls, late at night reporting that she felt unwell.
Halls told the inquest that one of Dack’s messages, sent at around 11.30pm, said: “He put something in my drink.”
Forensic toxicologist Mark Tyler said Dack’s body did not have high levels of alcohol or other substances.
He said there were low levels of GBH – a date rape drug – or gamma hydroxybutyrate in her blood and urine samples but Tyler said it was “quite possible” that these had been generated naturally by the body after her death.
Howard was questioned by police on suspicion of administering a noxious substance following her death but no further action was taken because of a lack of evidence, the inquest was told.
The coroner said that Dack had been exhibiting “unusual” behaviour on the night before her death, “following which she had expressed an intention to take her own life”.
A message from Dack to Halls at about 1:30am on the morning that she was reported missing, stated: “I am going to go for a walk, I am going to die…”
The coroner pointed out that she was “a young woman with no recent history of mental health issues”.
Her father Matthew Dack told the inquest that his daughter has “always been a happy, caring, loving person, beautiful inside and out, and truly the best daughter anyone could ask for”.
Dack’s mother Dawn Howell added that her daughter was an “absolute delight to be with” and her manager at work “could only describe her in one word and that was ‘perfect’”.
Not enough evidence to decide cause of estate agent’s death says coroner - Property Industry Eye