A police force has referred itself to the Independent Police Complaints Commission for taking six days to work out notorious British criminal John "Goldfinger" Palmer died of gun shot wounds, rather than natural causes.
The body of Palmer, 64, was discovered by his family at an address in South Weald, Brentwood, on June 24 and Essex Police initially recorded his death as not suspicious.
But six days later, on Tuesday, a post-mortem determined he died from gunshots to the chest, an error a former flying squad commander has labelled "one of the most terrible mistakes in policing I've ever heard of".
A force spokesman told the Mirror: "Police and paramedics who attended the scene initially assessed the death as non-suspicious due to pre-existing injuries due to recent surgery. Closer inspection raised doubt and a post-mortem was conducted to establish the cause of death."
Essex Police said on Thursday that it had asked the IPCC to investigate possible failings.
Former Metropolitan Police chief John O'Connor accused Essex Police of being "utterly incompetent".
He told the Sun: "When someone as notorious as John Palmer is discovered dead on your patch then surely it's common sense to be absolutely sure of the facts about how he died.
"But one minute these bunglers were saying it was natural causes then almost a week later it's suddenly murder. What a joke.
"It's one of the most terrible mistakes in policing I've ever heard of."
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Detectives would be "days behind" in the investigation and may have "completely lost the crime scene", he added.
Palmer was cleared of handling proceeds from the £26 million Brink's-Mat bullion raid at Heathrow in 1983, but his alleged involvement earned him the nickname "Goldfinger". Palmer is yet another victim of the 'Brinks-Mat' curse, which has claimed the lives of more than 20 people who came into contact with what was dubbed 'fools gold'.
In 2001 he was jailed for timeshare fraud, after building a multimillion-pound business that cheated thousands of Britons who wanted a holiday home in the sun.
Palmer had spent the last eight years on bail following his arrest in Tenerife in 2007, where he was charged with fraud, firearm possession and money laundering.
While on bail Palmer was said to be dividing his time between Essex and Tenerife, and it is claimed that just days before his death the career criminal had been told he could face up to 15 years behind bars in Spain.
Detective Chief Inspector Simon Werrett, who is leading the murder investigation, said police want to speak to anybody was was around Sandpit Lane between 4pm and 6pm on Wednesday June 24. The area is rural but is often used by dog walkers and joggers, he said.