British police offered a reward of £20,000 (22,800 euros, $31,600) on Thursday for information about the murder Imran Farooq in London one year ago.

Imran Farooq was attacked as he returned home from work on September 16, 2010. A post-mortem found he died from multiple stab wounds and blunt trauma to the head.

“Imran Farooq was killed in a brutal manner outside his own home and his death has left the community with a deep sense of loss,” said Detective Chief Superintendent Neil Basu of London’s Metropolitan Police.

“We still believe there are people out there who hold vital information that could assist the investigation, and have not yet come forward.”

Although they remain open-minded about the motive, police said they believe the attack would have required careful planning and Farooq’s killers may have had help, including from innocent people.

“Detectives want to hear from anyone who was asked for information about Dr Farooq and his routine, or who was asked to help buy items, such as knives similar to those used in the murder, or mobile phones around the time of his murder,” Scotland Yard said in a statement.