More than a dozen people who were injured in a stabbing attack at the central train station in the German city of Hamburg were in stable condition, police said Saturday. A 39-year-old woman, a German national, was arrested at the scene of Friday’s attack without putting up resistance and police said they believe she acted alone. The Hamburger Abendblatt newspaper reported that two passersby managed to overpower the woman and take the knife from her. It quoted a fire department spokesman, Philipp Baumann, saying that the attack injured 18 people between the ages of 19 and 85. Three women aged 24, 52 and 85, and a 24-year-old man were critically injured. According to the police, however, all four were in stable condition on Saturday. There was no immediate indication of any political motive, and police said that investigators were looking into whether the suspect may have been mentally ill. The woman was expected to appear before a judge on Saturday and then placed in a psychiatric ward.