A man who fell ill in the back of a police car after he was arrested for allegedly driving under the influence of drugs has died, his family’s lawyer Richard Korver has said.

Video footage of the incident in Hengelo, Overijssel, last week, shows officers dragging him out of the car, apparently unconscious, before one of the officers pinned him to the ground by putting his knee against the man’s chest.

The 37-year-old man was taken by ambulance to a hospital in Hengelo, where he died on Thursday.

Korver told NOS: ‘He was 37 years old and in good physical health. He was arrested because of a suspected traffic offence, so it’s a bit strange that he ended up dead.’

Police said they had stopped him in Borne, 6km north of Hengelo, and took him to the town’s police station for a blood test after a saliva test showed he had taken drugs, a spokesman told local broadcaster RTV Oost.

Why the policeman put his knee on the man’s chest is unclear. A police spokesman told the broadcaster ‘it may have been standard procedure’. A second video, which appeared shortly after, shows five officers standing around the man, one of whom puts his foot on the man’s leg.

The matter is now in the hands of the Rijksrecherche, which investigates criminal conduct by members of public bodies.

The family of the man, who RTV Oost said was a member of the Syrian community in Hengelo, also want the matter cleared up and has asked Korver to represent them.

In an unrelated incident on Thursday another man became unwell in the back of a police car and later died in hospital. In Eerbeek, Gelderland, a 37-year-old man who was showing erratic behaviour was handcuffed and taken by police to a mental health crisis centre for assessment when he lost consciousness. He was given first aid but died later in hospital. The Rijksrecherche is also investigating this case.