Police say five masked people stormed a coffee shop in central Germany with a machine gun, sprayed tear gas and stole about 8,000 euros ($8,950) before escaping by car.

Hesse police said one guest was injured by the tear gas and had to be treated in the hospital after the robbery early Monday in the town of Oberursel. The German news agency dpa reported most of the stolen money belonged to the coffee shop owners, some of it to the guests.

Police used a helicopter to search for the armed group but have not yet found them. They're asking possible witnesses to come forward.

The robbery happened after the coffee shop had closed around 4 a.m. Dpa said most of the guests were likely acquaintances of the owner.