Two men were sprayed in the face with an ‘unknown substance’ in a suspected homophobic attack.
Detectives are appealing for two further potential victims to come forward after the incident in south London.
The corrosive substance assault on two men was a “completely unprovoked and targeted” attack, police said.
Police were called to McDonalds in Lambeth at 4am on Saturday, 19 January, where they found two 22-year-old men who said they had been attacked at a bus stop.
The men reported they had been sprayed in the face with a noxious substance, believed to be pepper spray, by a man in a hate crime attack.
They were treated at the scene by paramedics, but did not require hospital treatment.
Detectives investigating the assault have identified that two other men may have been the victims of a similar attack in a nearby KFC 20 minutes earlier on the same night.
Detective Constable Amy Cross, of Lambeth CID, said: “This was a completely unprovoked and targeted assault on at least two members of the public, with a possible further two victims not yet in contact with police.
“Both the attack and the homophobic motivation of this assault are abhorrent and I appeal to anyone with any information that could assist the investigation to come forward.”