An alleged knifeman has been captured on video running towards a woman with a pram, just moments after he allegedly killed one man and injured two others.

The man, who has not been publicly identified, was arrested in the backyard of a property on Smythe St in Merrylands, in Sydney’s west, following an alleged stabbing spree at about 10am on Tuesday.

Two people were raced to Westmead Hospital in a critical condition, including a 22-year-old man with neck injuries and a woman, 47, with wounds to her abdomen and chest. 

Another man, aged between 30 and 40, died at the scene.

Security footage filmed on Railway Terrace showed the alleged killer dressed in a white shirt and hat, and walking with his hands on his hips – as though he was out of breath.

He could then be seen running past a woman pushing a pram.

Police said the man stabbed multiple people with what was believed to be a kitchen knife up to 30cm long, before he fled the scene.

The man was arrested and taken to Granville Police Station.

An alleged knifeman has been captured on video running towards a woman with a pram, just moments after he allegedly killed one man and injured two others

One person has died and two others have been wounded after a stabbing in western Sydney

The trio were attacked in the suburb of Merrylands at 10am on Tuesday

Paramedics treated three people at the scene, with two left in a critical condition 

No charges have been laid. 

Police said they have recovered a weapon, though it is unclear if it is the knife understood to have been used in the stabbing. 

A crime scene was established spanning 50 metres along Merrylands Road, where the alleged victims were attacked.

Guildford resident Joseph Ruissi told the Daily Telegraph he saw a man tending to the female victim’s neck in the aftermath of the attack.

‘Blood was pouring down the side of her neck and across her chest and she was coughing blood from her mouth,’ he said.

He said the shopkeeper was trying to staunch the bleeding, adding: ‘She started to slump to the side and you could tell she was dying.

‘Every second felt like a year. It was absolutely terrible. I just pray to God that whoever survived is going to get better.’

Superintendent Simon Glasser said the incident was ‘highly confronting’. 

The knifeman is seen in the CCTV footage with the woman pushing a pram

One person, who has yet to be formally identified, died at the scene 

A short time later, a man was arrested on nearby Smythe Street 

Police said the knifeman had stabbed multiple people with what was believed to be a kitchen knife up to 30cm long outside Binas Mini Mart

‘It’s a horrible offence to have taken place in Merrylands just prior to lunchtime with lots of people around,’ he told reporters.

He said there was no relationship between the three victims, who were by themselves on Merrylands Road when the stabbing occurred. 

‘The alleged offender is known to police for petty crime and a number of mental health incidents,’ Superintendent Glasser said.

‘He is not linked to the address he was located. 

‘However, he is a local to the area.’

Supt Glasser said ‘most of his history with us is mental health-related’. 

Once charges are laid, the alleged killer will face court.