Task: Question Answering
Input (English): Context: Upon receiving a divorce in Reno, Helen Trent (Claire Trevor) plans to return to San Francisco and goes back to the boarding house where she is renting a room from Mrs. Kraft (Esther Howard) but discovers two dead bodies in the kitchen. Sam Wild (Lawrence Tierney) is the murderer and has committed the crime out of a jealous drive - one of the bodies was his girl friend Laury Palmer (Isabel Jewell) and the other a new man she was dating. Helen grabs her bags and heads for the train and coincidentally Sam does too pushed by his close friend Marty Waterman (Elisha Cook, Jr.) who stays in Reno to get details on the murder and agrees to meet Sam later. Coincidentally Sam and Helen meet on the train and are attracted to each other in part because in a casino earlier they had flirted across the Craps table. In San Francisco Helen parts with Sam but he crashes in on her and her fiancee Fred Grover (Phillip Terry) and her half-sister Georgia Staples (Audrey Long) who has inherited a large newspaper company. Sam sees a good thing in Grace and successfully seduces her into marrying him partly for the power her money can bring him but also to sustain the attraction he has for Helen. Mrs. Kraft hires seedy private detective Matthew Arnett (Walter Slezak) to find out who killed her good friend Laury and the shamus arrives on the wedding day of Sam and Georgia. Helen manages to leak some information to Arnett but Sam discovers this as well and gets his buddy Marty to track down Mrs. Kraft to put an end to things. But this plan goes awry when Marty stops to try to get more information from Helen and Sam perceives it as a play for the woman. Sam reacts in a jealous pique and Helen realizes that he must be stopped and calls Arnett to bring the police with the information he has gathered from his investigation. Sam discovers Helen's communication with Arnett and pulls his gun just as the police arrive resulting in a climactic shootout. 
 Question: What profession does Walter Slezak play in the film?
Output (English): detective