A man remains critically ill in hospital after being attacked in west London on Christmas Eve.
Police have urged anyone who saw the 40-year-old being assaulted in Southall to contact them.
The victim was left with serious head injuries after the attack in Regina Road at about 2240 GMT.
Det Insp James Raphael, of the Met Police, said: "We are particularly keen to speak to anyone who may have seen anybody running away from the scene."
Three men, aged 34, 35 and 50, have been questioned and released on bail over the incident.