The family is feared to have been deliberately targeted in the horror in Clapham, South West London, last night.
Abdul Shokoor Ezedi is now being hunted by police, who have urged the public not to confront him and instead call 999 immediately.
Cops have now released a new photo of Ezedi, which shows major injuries to his face.
Superintendent Gabriel Cameron said: “We are now releasing an image of the last known sighting of Abdul Shokoor Ezedi, which was on Caledonian Road, N1 at 20:48hrs on Thursday, 31 January.
“The image is taken from the Tesco store, where Ezedi is believed to have purchased a bottle of water. He left the shop and turned right.
“The image shows Ezedi with what appears to be significant injuries to the right side of his face. This makes him distinctive.
“If you see Ezedi, call 999 immediately. He should NOT be approached.”
Police today confirmed 12 people were injured in the attack – including the 31-year-old mum and her daughters, aged three and eight.
None of their conditions are believed to be life-threatening, although the mum and her youngest child’s wounds could be “life-changing”.
Three women, aged in their 30s and 50s, were also hurt when they heroically rushed over to help the family.
A man in his 50s suffered minor injuries when he also stepped in, along with five police officers who raced to the scene.
Although it was previously believed to be an acid attack, police confirmed an alkaline corrosive substance was used.
Anyone with information has been asked to call police on 101 quoting reference CAD 7790/31Jan.