A reward of up to £20,000 is being offered for information leading to the arrest of the suspect in a chemical attack on a mother and her daughters in Clapham, police have said.
Abdul Shokoor Ezedi was last seen leaving Tower Hill Underground station on 31 January at 21:33 GMT, the Metropolitan Police said.
People who know where he is have yet to come forward, detectives said.
The injured woman, known to Ezedi, is critical but stable in hospital.
The attack – carried out with a corrosive substance – took place on Lessar Avenue, Clapham at 19:25 on Wednesday.
The mother, 31, is said to have experienced life-changing injuries while her daughters, aged three and eight, suffered injuries not “as serious as first thought”.
The Met’s Cdr Jon Savell said a laboratory analysis of the substance from the attack site found it was a “very strong concentrated corrosive substance, either liquid sodium hydroxide or liquid sodium carbonate”.
“Further enquiries are ongoing including comparison with the containers seized from Ezedi’s address in Newcastle,” he added.
Dozens of calls have been received by the Met following an appeal, and searches have taken place at two addresses in east London and three in Newcastle.
Since the attack on Wednesday night, police have revealed more information on Ezedi’s movements.
The 35-year-old left the Newcastle area in the early hours of Wednesday before travelling down to the capital.
CCTV footage shows Ezedi at a Tesco shop in Caledonian Road, Islington, north London, on Wednesday at 20:38.
At 21:00, he was captured on CCTV entering King’s Cross underground station and boarding a southbound Victoria line train. An image released by police pictured the man with significant injuries to the right side of his face.
He arrived at Victoria at 21:10 and changed trains to travel eastbound on the District Line at 21:16, police said.
Cdr Jon Savell said he was “hugely grateful” to the public for the “significant number of calls” the force had received, saying: “Your help is critical.”
“I must warn anyone who is helping Ezedi to evade capture – if you are harbouring or assisting him then you will be arrested,” he added.
The Met is working with the Home Office, UK Border Force, UK Visas and Immigration, the National Crime Agency, British Transport Police and several other police forces in the search.
Details of Ezedi have been circulated to all UK police forces and ports, police said.
Appealing directly to Ezedi, Darius Nasimi, of the Afghanistan and Central Asian Association charity, said: “I want you to go straight to a police station immediately.
“You have a serious injury that needs to be seen to but, more importantly, you must do the right thing and hand yourself in to police.
“This has gone on for long enough.”
Anyone with information about the suspect is being asked to contact the police on 020 7175 2784 or for an immediate sighting dial 999.