Note: Before you can accept this mission you must unlock the Mad Mile ctOS Center. This can be done earlier in the game or undertaken directly before.
Head to the car showroom in Mad Mile and hack the access point, which is an easy yet timed puzzle. Inside, you'll spot Crispin picking out his new ride and then given the objective to eliminate him and hack his phone. Crispin hangs out in a back room where you can't target him and any action on the guards will alert him, causing him to hop in his new ride and drive away.
Aggressive Route - Proximity Escape
Head along the side of the building toward the back where Crispin is and hide behind the planter directly in front of his car. Equip the Proximity IED and toss it on the ground where the car will exit so that when you draw attention he will hop in the car and drive right into the IED, killing him. You can then quickly hack his phone and choose to either fight the enemies or escape in one of the nearby cars.
Stealth Route - Lure Him Out
Crispin is a little jumpy and any noise will draw his attention. If you head to the same side of the building as the one above, the side that his car is facing, you can grab one of the nearby cars and hit a lamp post. This will cause Crispin to leave the office and investigate, allowing you to kill him with a melee strike. You can then quickly hack his phone and choose to either fight the enemies or escape in one of the nearby cars.
After dealing with the business at the showroom you can make your way to the next waypoint, Club Infinite 92. Enter the building and follow the host to the back room, where you may recognize the young lady on the table, and watch the scene.