You will be given a definition of a task first, then some input of the task.
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: A suicide bomber detonates himself at a party in Java, Indonesia, and a Javanese Sultan's daughter, Sultana, is believed to be one of the unidentified victims. Jake Travers, an American posing as a graduate student from Cornell University, was at the scene of the blast and is held as a witness by a police detective of Detachment 88, Lieutenant Hashim. 
After interviewing Jake at the crime scene, Hasim and Jake are attacked by terrorists led by Malik and his henchman Achmed. Jake saves Hashim and kills two terrorists, but Achmed manages to escape. Hashim becomes suspicious after he observes Jake's combat skills. Jake and Hashim are brought to the hospital where Hashim's wife meets Jake. At Hashim's wife's insistence, Hashim invites Jake to their house for breakfast. At the house, Hashim tells Jake that he ran a background check on him through Interpol. Jake tells Hashim he is an FBI agent conducting an undercover investigation, and suggests they cooperate with one another. 
Returning to his apartment, Jake faxes to a friend stateside a photo of a tattoo from the corpse believed to be Sultana's. Jake's friend informs him that the tattoo is typically used by Chinese high-class prostitutes, which confirms Jake's suspicion that the body is not Sultana's.
Jake follows a lead to a night club, where he brings home a prostitute bearing a similar tattoo. When the prostitute cooperates with Jake, they are ambushed by Hashim's terrorists and a Chinese gang operating the prostitution ring. The police, who had been covertly surveilling Jake, intervene and suffer casualties in the fight. Jake flees the scene, but the police eventually capture him.
Output:
Who begins to suspect an American posing as a graduate student after observing his combat skills?