A 27-year-old man was taken to hospital with broken bones after being ambushed by four Asian men armed with a baseball bat in a Hounslow alley.
The victim had been running along Hanworth Road at 11.40pm, on June 6, when he was chased down the alley and assaulted.
It is believed there had been some dispute between the man and his attackers earlier in the day. He was treated at hospital and later sent home.
One man was arrested near the scene and has been interviewed and bailed, and officers intend to make further arrests next week.