Three people have been killed and four others injured by a gunman who opened fire in a spa in Wisconsin.

Authorities say they have found an improvised explosive device inside the Azana Salon and Spa in Brookfield, a suburb of Milwaukee. Bomb experts were at the scene.

Police have identified a suspect as Radcliffe Haughton, but they do not have him in custody. Police provided no other details about the possible motive for the shooting.

Brookfield police chief said the situation remains “fluid.”