The relative, who has not been named, said they would “bring in” 35-year-old suspect Abdul Ezedi themselves and expressed concern about his wellbeing.
In an update on Saturday, police revealed new footage of a raid in Newcastle, one of five carried out in properties in Northumbria and London, during which “significant” evidence was found.
The evidence uncovered in the overnight raids included containers featuring a “corrosive” warning, which are now being forensically tested to see if they match the corrosive alkaline substance used in the attack on Wednesday night in Lessar Avenue.
It came as the hunt for Ezedi entered its third day, with the Met Police saying it had received dozens of calls with information about possible sightings.
Speaking about the wound seen on the suspect’s face on CCTV footage, the relative told Sky News: “His injury is very bad and he needs medical attention. I will bring him in by myself if I have to.”
Ezedi, who came to the UK from Afghanistan, attempted to drive away from the scene but crashed into a stationary vehicle and fled on foot, police said.
He then boarded a tube at Clapham South underground station and travelled to King’s Cross. He was last seen boarding a southbound Victoria line tube at 9pm on Wednesday night.
A total of 12 people were injured in the attack. Ezedi allegedly threw the three-year-old girl to the ground like a “ragdoll” as witnesses heard the mother screaming “my eyes, my eyes”.
Three women, who tried to defend the family, were injured and taken to hospital. Five police officers were also taken to hospital. A man in his 50s was also injured but refused hospital treatment.
Met police commander Jon Savell said: “We have received dozens of calls with information, including possible sightings, and every single piece of information has been recorded and forms part of our ongoing investigation.
“I can assure the public that my colleagues and I are fully committed to using every available tool and tactic for as long as it takes to find Abdul Ezedi.”
Previously, he said: “Abdul, you clearly have got some very significant injuries. We’ve seen the images. You need some medical help, so do the right thing and hand yourself in.”
And as the manhunt was stepped up, it emerged that Ezedi was understood to have been convicted of a sexual offence in 2018, before being granted asylum in 2021 or 2022.
He had previously been twice refused asylum after arriving from his native Afghanistan in 2016. Members of the public were being warned not to approach Ezedi and to dial 999 instead.
For almost a year, Ezedi had lived in accommodation provided by Action Foundation, which houses and provides support to migrants.
Chief executive Duncan McAuley said: “We’d like to first of all express our sympathy to the people involved in this shocking incident.”