Police investigating the racist murder of a taxi driver in Huddersfield believe his death may be linked to a disturbance in the town six weeks ago.
Mr Pervaiz had worked as a taxi driver for the last seven years
Father-of-three Mohammad Parvaiz, 41, was found with serious injuries at Field Head, Golcar, on Saturday night. He died later in hospital.
A post-mortem examination found he died from head injuries.
Four males and three females, aged between 16 and 19 years old, were arrested in connection with the attack.
West Yorkshire Police said the three girls had been released without charge and a fourth female was released on Monday pending further inquiries.
Police said racist language used during the attack on Mr Parvaiz, who was born in Pakistan, meant his killing was being treated as racially aggravated.
Det Supt Tim Forber, who is leading the inquiry, said Mr Parvaiz's death was believed to be linked to a disturbance between two groups in Golcar on 11 June.
He said no-one was injured but a scooter was damaged during the incident.
Det Supt Forber urged anyone who could have seen the attack or the disturbance in June to contact police.
"Whilst we are keeping an open mind regarding the motive for this attack, it is believed racist language was used towards the victim at the time.
"For this reason the incident is being treated as racially aggravated at this stage."
Windows were smashed on the dead taxi driver's vehicle
Police have set up an incident room and anyone with any information is asked to ring 01924 431000.
Mr Parvaiz, who moved to England from Pakistan in 1994, had been a taxi driver for seven years.
He lived in Birkby, Huddersfield, with his wife of 15 years, two sons aged three and 12 and a nine-year-old daughter.
Local Lib Dem councillor Andrew Marchington said: "We are shocked and appalled by what has happened.
"Our thoughts are with the friends and family of the dead man involved in this incident."