Thunder Bay police are looking for a second suspect after an armed robbery. Officers responded after the Shell on Arthur Street was robbed last night just after 8 o'clock. A 22 year was arrested but a second man is still missing and could be armed with a knife. Police had to deal with another armed robbery of a Mac's Mart, this time the thief was armed with a stick. The man entered the Mac's Mart on North May street around 2:30 yesterday morning and made off with some cash and cigarettes. Police also had to deal with a stabbing over the weekend. A woman stabbed a man during a domestic altercation and is facing assault charges. The man received minor injuries.