A bottle of "ignited liquid" thrown at an employee of a halal butchers is being treated as a potential racist attack.
West Midlands Police said the incident took place on Wednesbury Road in Pleck, Walsall, at about 17:20 BST on Monday.
The worker was bruised by the bottle, while the shop suffered fire damage.
Officers are looking for a man described as white and about 6ft tall who was seen on CCTV entering the shop.
A police spokesman said: "One of our lines of investigation is to determine if this is a racially-motivated assault."
Det Insp Greg Evans said officers were "keeping an open mind as to the motive".
"The man was not seriously injured, but it could have been much more serious," he said.
Valerie Vaz, MP for Walsall South, said she had been in touch to offer her support to the owners following the "shocking" incident.
She also spoke of her concerns about the recent rise in reported hate crimes since last week's referendum on EU membership.
"Although it is reported that the police are keeping an open mind over the motive of the attack, since the referendum result we have witnessed a surge of racially-motivated incidents nationally," she said.
"This increase in hate crime is deeply disturbing."
West Midlands Police said it had received 20 incidents of reported hate crimes following the referendum, but this was in line with the average the force had recorded since April.
Chief Constable David Thompson said reports of hate crime were being "carefully monitored", adding it is "no surprise people are feeling insecure" following a referendum debate "that has had a forceful debate on immigration, our relationship with Europe and national identity".
"We must offer strength and friendship for those feeling vulnerable and show intolerance to hateful behaviour in our communities," he said.