A pet shop assistant suffered serious burns when an attacker threw what is believed to be acid in his face.
Police in Rugby are awaiting the results of a full analysis of the corrosive liquid but say they believe it was either sulphuric acid or caustic soda.
The 37-year-old, who works in the Pets and Poultry store in West Leyes, is described as in a serious condition in hospital with burns to his face.
Detectives hunting the attacker said a man entered the shop shortly after 1400 GMT on Thursday and threw the liquid into the face of the employee.
Running from scene
The assistant was taken to the Coventry and Warwickshire Hospital where he is expected to remain for several days.
Officers want to hear from anyone who witnessed the incident or saw a man running from West Hayes around the time of the incident.
He is described as wearing a dark coloured top, with the hood pulled closely over his face.