At least four people were injured Sunday when a small homemade bomb exploded at a trade fair in the Bangladeshi capital, police and hospital sources said, according to AP. Police investigators said the blast was caused by a crude bomb _ a small tin pot filled with explosives and nail splinters _ near a gate as visitors queued up to enter the Dhaka Trade Fair. Police suspect the bomb was hurled by muggers fleeing the scene, an officer at a control room inside the venue said. Such crude bombs are often used by criminals to create panic in Bangladesh.