Detectives are appealling for witnesses after five people were sprayed with an ammonia-based liquid during a disturbance at Clacton.
The incident happened at Burger King in Stephenson Road at about 3.30pm on Monday, September 14.
Two men walked into the restaurant and sprayed the fluid at four other men who were waiting for food. All six then ran from the restaurant. Another man, who was not connected to the suspects or victims, was caught up in the melee and had fluid sprayed in his face. He later required treatment for an eye injury.
About two hours later police were called to Hayes Road, Clacton following reports of a fight involving men armed with baseball bats and hockey sticks. Detectives believe the incidents are linked.
Investigating officer DC Rob Dines told Radio Essex: “There were a few other customers in Burger King at the time and we would like to hear from anyone who was caught up in the altercation and was accidentally sprayed or affected by the substance.
“Following the incident, two men ran from the restaurant and towards the car park entrance. One of them was back and was wearing a black T-shirt and the other was white and wearing a red baseball cap.
“The area around the Shopping Village was busy and we would also like to hear from anyone who saw the men or saw a vehicle leave the area at speed.
“After the incident at Hayes Road a man contacted police and gave some information but did not give his details. We would like him or any other witnesses to contact us.”
Anyone who can help should contact DC Dines or his colleagues at Clacton CID on 101 or call Crimestoppers anonymously on 0800 555111.