Meet up with Clara in The Loop for a scene and then locate the camera on the light pole nearby. Follow the feed to the camera to access the Camera HDD for another scene and get your next target, a homeless man names Tobias. Follow Clara, listening to her story, until you reach Tobias' shop and can check the surrounding area.
There are numerous crafting materials in the area, but the one thing you should be sure to get is the burner phone. The phone with the Audio File: Maurice Vega 02 is located in the southeast side of the search zone inside a box house by a picnic table.
Take out your Profiler and search the area for the man on the phone and hack into his conversation with Tobias. While the chat is going, make your way to the underpass toward the car, you'll need it in a minute. Once the Fixers head off for Tobias you'll want to rush after them, using the Traffic Lights to stop or slow them down. By now you should be pretty capable of taking out a target in a car, so do so and then either escape or kill his lackeys.
Head for the waypoint in Parker Square and make your way into the suspicious basement where Tobias is enjoying poker. Sit down to join them for a hand of Texas Hold 'Em and enjoy the game, for the very short time you can, while Aiden slowly probes Tobias with questions. It won't be long before Tobias gets spooked and bolts.
Chase Tobias down quickly, jumping over the ledges to catch up, and tackle him to complete the mission.
Note: You can return to the house for some Hold 'Em at any time. This and other Mini-Games are available throughout the city. Tobias' Shop is also open and offers a variety of crafted tools ready-made.