A teenager was taken to hospital after being attacked in a West Lothian street during the early hours of Saturday morning.
The 16-year-old boy was seriously assaulted in the George Street area of Bathgate between 1.15am and 1.30am.
He was taken to St John’s Hospital in Livingston for treatment.
Investigating officers are reviewing CCTV in the area and conducting enquiries to establish the full circumstances of the incident.
They are also keen to identify four men dressed in dark clothing who are believed to have been involved.
Police believe late-night revellers may have witnessed the attack.
DC Alan Gibson, from Livingston CID, said: “Whilst we don’t have descriptions of the suspects, the assault took place near a bar on the opposite side of the road, so it is likely that patrons have either seen the incident itself or these men running from the area.
“I’d ask members of the public with information to contact Police Scotland and assist us with our enquiries.”