A man was stabbed and a woman hit by a bottle, leaving her needing 40 stitches to her ear, in an attack at a bar.
They were in the beer garden at the front of the Virtue bar in Mile End, east London, on 1 June when they were assaulted by five men, police said.
The men threw bottles, injuring the woman, 29, and then assaulted the man stabbing him in the stomach and back.
Det Con Danny Bryant said the man, aged 24, lost a lot of blood and was lucky he was not more seriously injured.
The gang then chased the male victim along Mile End Road and continued to assault him, police said.
It is thought the attackers ran off into Rhonda Grove where they got into a dark coloured vehicle.
A knife was recovered from the scene.
The victims were taken to the Royal London Hospital for treatment and have since been discharged.
A 25-year-old man was later arrested at a London hospital in connection with the attack.