Police have released further details of an attack near Walthamstow Fire Station as part of an appeal for information.
A 35-year-old man suffered facial injuries in the incident, which happened on Monday lunchtime.
It had been believed that the attack took place in the street because police taped off part of the pavement outside the station in Forest Road.
But it has now emerged that the assault occurred at a house next door.
A Met spokesman said three men knocked on the door of the property at around 12.20pm and attacked the man when he answered.
They went inside and grabbed a 19-year-old woman who they then gagged and tied up.
Police were called but the trio escaped before officers arrived.
Detectives say they are keeping an "open mind" with regards to the motive and there are no reports of anything being stolen.
The man who was attacked was rushed to hospital as a medical priority but he has since been discharged.
Police have released descriptions of the three suspects.
The first is a white man aged between 30 to 35. He is about 5"9 and was wearing dark clothing.
The second is a white man aged between 25 and 30. He is about 5"11 and was also wearing dark clothing
The third suspect is a mixed race man aged between 28 and 29. He is 5"7 and was wearing white Adidas trainers, black gloves, white jeans and a dark zip up jacket without a hood.
A Met spokesman said: "Police are urging anyone with any information about this incident to contact Detective Constable Ray Anderson from Waltham Forest Police on 0208 721 5048.
"To remain anonymous call Crimestoppers on 0800 555 111."