A manhunt has been launched over the fatal stabbing of a woman who was pushing a baby in a pram.
Police have released images of a man wanted over the attack in the centre of Bradford at 3.21pm on Saturday.
Habibur Masum, 25, is from the Oldham area and has links to Burnley and Chester. He is described as an Asian man, of slim build.
Officers were called after reports a woman had been stabbed by a man who then fled the scene.
She was taken to hospital where she subsequently died of her injuries. The victim is yet to be formally identified but is understood to be 27 years old.
Masum was pictured on CCTV wearing a duffle coat with three large horizontal lines of grey, white and black, light blue or grey tracksuit bottoms with a small black emblem on the left pocket and maroon trainers.
A witness also reported seeing him wearing a grey hoodie with the hood up. He ran over to try and help the woman.
"She was on the ground. I tried… there was me, and another guy, we tried. But looks like she was gone," he said.
He said he saw the victim the morning she died, with her child.
"The child is very small. I think it must be two to four months, something like that.
She was walking with them all the time.
"What is he going to do when he grows up without mother?"
Police encouraged the public not to approach Masum.
“A knife was recovered from the scene of the murder, but we cannot say if Habibur Masum is armed,” said Detective Chief Inspector Stacey Atkinson, of West Yorkshire Police’s Homicide and Enquiry Team.
“If anyone has any information about his movements or whereabouts since 3:20pm on Saturday please contact police as a matter of urgency.”
