An elderly man out walking with his partner was assaulted by a group of men after he challenged them over their behaviour.
The couple spotted a group inside a parked car who appeared to be taking drugs and behaving anti-socially in Harehills.
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When the 71-year-old man challenged them, they left the vehicle and punched him to the ground.
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He suffered a head injury described as 'horrid' by a special constable who attended the scene.
West Yorkshire Police said:
"Police are investigating a report of an assault on Chatsworth Close, Harehills on 3 December at around 7.45pm.
"A 71-year-old man and a 58-year-old woman approached the occupants of a parked car who they believed were acting anti-socially.
"They confronted the suspects who then assaulted them, punching the male and causing him to fall to the ground.
"The suspects then made off in the vehicle.
"The male victim was taken to hospital for treatment for a head injury. The female was uninjured.
"Anyone with information is asked to contact police on 101, quoting crime reference 13180606281."