A man in distress called police for help but ended up dying after he was restrained by officers.
The man, who was said to be having a mental health crisis, had called Hertfordshire Police asking for help before 11pm on October 7.
Police were then called by a concerned local shortly after to an area of Eleanor Cross Road in Waltham Cross, Broxbourne, following reports of a man running around in the street.
When they arrived, they deployed a pepper-spray-like substance called PAVA and then restrained the man.
The 31-year-old man who remains unnamed, then struggled to breathe and an ambulance was called but he was pronounced dead at 12.17am.
The police watchdog, which revealed the man originally called police looking for help, is now appealing for witnesses to come forward as they continue to investigate the circumstances surrounding his death.
The Independent Office for Police Conduct (IOPC) confirmed that the man was mixed-race (black Caribbean and white).
Witnesses in the area said that the man had been walking around with half of his faced bloody and that he looked clearly in distress.
Another witness said that the man had entered their garden before climbing the fence into an alleyway between houses.
They say that officers soon arrived and an ambulance was called.
A spokesperson for the IOPC said: “The Independent Office for Police Conduct (IOPC) is appealing for witnesses as our investigation continues into the circumstances leading up to the death of a man following contact with Hertfordshire Constabulary on Friday 7 October.
“A 31-year-old man from Waltham Cross was pronounced dead at the scene in Eleanor Cross Road, Waltham Cross, Hertfordshire.
“A post-mortem examination was held on Tuesday 18 October, and further tests have been requested. A date for an initial inquest hearing has yet to be set.
“We have established that, shortly before 11pm on 7 October, Hertfordshire Constabulary officers received a call from the man asking for help from police. When police officers attended the man appeared to be in distress and he became unwell at the scene.
“An ambulance was called and the man received treatment, but sadly died.
“IOPC investigators attended the scene and the post-incident procedures, where initial accounts were given by the officers involved. We declared an independent investigation on the morning of 8 October."
IOPC regional director Graham Beesley said: "An investigation is underway to establish the circumstances surrounding this incident and examine the officers’ contact with the man before he died.
"We have spoken with the man’s family to explain our role and offer our condolences at this tragic time,” he said.
"Any time a person dies following police contact it’s important that a thorough, independent investigation is carried out.
"Our investigators are reviewing evidence including body worn footage and we want to speak with anyone who was in the area around Eleanor Cross Road between 10pm and midnight on 7 October and witnessed any of the incident."
Anyone with information about this incident is asked to contact the IOPC investigation team by emailing walthamcross@policeconduct.gov.uk
