"Significant evidence" has been found by police searching for a chemical attack suspect.
Detectives have urged Abdul Ezedi to "do the right thing" and turn himself in, as a nationwide manhunt continues.
He is suspected of throwing an alkaline corrosive substance at a woman and two children in Clapham, south London, on Wednesday night.
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Police said the 31-year-old mother injured in the attack is still in hospital and under sedation. They expect her injuries will be life-changing.
However, the injuries of the two children are not as serious as first feared.
The four bystanders who rushed to their aid have all been released from hospital with minor burns and five police officers who were also injured are back on duty.
Giving an update on the manhunt, Metropolitan Police Commander Jon Savell said "important" pieces of evidence had been recovered in searches carried out in east London and Newcastle on Thursday night.
He said: "In terms of our manhunt for Ezedi, we've got a large team of very experienced detectives leading the manhunt, using all the tactics that you would expect us to use, lots of officers out on the ground.
"We're working very closely with colleagues from Transport for London, British Transport Police and our colleagues in Northumbria Police as well.
"Last night, five search warrants were executed - two in east London and three up in Newcastle. We've recovered some significant and important pieces of evidence which will help with our investigation."
Describing Ezedi's movements in the run-up to the attack and immediately after it, Commander Savell said he left Newcastle in the "very, very early hours" of Wednesday and travelled south to London.
By around 6.30am he was in the Tooting area of the capital.
There was then a sighting of his vehicle at about 4.30pm in Croydon and by around 7pm he was in Streatham.
The "awful attack" took place at 7.25pm in Clapham.
At 7.33pm he boarded a tube at Clapham South Tube station.
By 8pm he was at King's Cross station and by around 8.45pm he was captured on CCTV, in a branch of Tesco on Caledonian Road, with a "fairly significant facial injury".
Police said the last confirmed sighting of Ezedi was at 9pm at Kings Cross Tube station, where he was seen boarding a southbound Victoria Line train.
Commander Savell added: "As you have seen from the image we have released of Abdul Ezedi, he has suffered a serious facial injury.
"I'm making a direct appeal - hand yourself in to police, not only so we can speak to you, but so you can get the urgent medical treatment you obviously need."
He went on to remind the public that if they see Ezedi not to approach him and call 999 immediately.