A woman brandishing a syringe cornered another woman in a lift, throwing punches and tearing out her hair.
Aisha Bangs, 32, is wanted by police after the attack on a woman in her 20s in flats in Ramsey Street, Bethnal Green.
The victim was able to escape and call police after breaking free.
Detectives say she had clumps of hair ripped from her head and was threatened with the syringe, but did not receive any other serious injuries.
She told police she saw a white man during the assault who she believes knew her attacker.
Anyone who knows where Bangs is or has any information about the attack which happened at 6.30pm on Friday 3 June, should call 101 quoting reference 4215040/16, or Crimestoppers anonymously on 0800 555 111.