A 75-year-old man stabbed to death yards from his home could have been targeted in a racially motivated attack, according to police.
Father-of-seven Mohammed Saleem, who used a walking stick, was stabbed three times in the back as he returned home from prayers at his local mosque in Small Heath, Birmingham, on Monday night.
The blows were struck with such violence they penetrated to the front of his body.
The elderly man also had "no defensive wounds" in what has been described as a "swift, vicious" and "cowardly attack" by the man leading the murder investigation, Detective Superintendent Mark Payne of West Midlands Police.
Officers now want to trace a white man, aged 25 to 32, of medium height and build, spotted on CCTV footage running near the scene of the attack around the time it happened just before 10.30pm.
Police also want to trace a seven-seat people carrier captured on CCTV, driving near the mosque with the two male occupants, both white men in their 30s, who are considered "significant witnesses".
In an emotional family appeal, two of Mr Saleem's daughters Shazia Khan, 45, and Nazia Maqsood, 44, called for the attacker to hand themselves in. They tearfully described their father as a "widely respected member of the community" and "much-loved father".
Mr Payne said the possibility it was a racially-motivated attack was "a significant line of inquiry" and a large number of detectives were working on the case. "To the attacker I say we will find you and we will bring you to justice," he said.
Mrs Khan, who lives in London, nodded firmly when the Press Association asked Mr Payne whether the police believed the attack to have been racially-motivated. She later said she believed it was "a pre-meditated brutal attack, pre-planned, intended to kill".
She said: "I cannot see him having any enemies being so full of hate to do this to him, he was an old man - that's what he was. He had no other agenda in his life, it's unacceptable and we just cannot believe an attack like this would happen to him. We just cannot understand it."