Dirty Deeds

Dirty Deeds is a side quest in Deus Ex: The Fall. It is obtained by talking to Cobra during the second main mission in Panama City.

Briefing
Diego, kingpin of the Skulls gang, has an ongoing feud with the arms dealer Cobra. Cobra has offered to scratch your back if you help him take Diego out. The Skulls leader has a pocket secretary which holds a list of valuable contacts. Find the list and give it to Cobra.

Get the Gang Leader's Pocket Secretary
Diego will be in his office in the southeast section of the Drug Lab. Go to the Drug Den in the slums and head to the second floor. Access the Drug Lab from here and get to Diego's office. Simply take him down or kill him to avail his pocket secretary.

Meet With Cobra
Cobra can be found in the alley behind Nightshades. Head to the club in the Boardwalk district. Take the path to the right of the club's front entrance. Once you see Cobra go talk to him. As a reward, you can choose between a Nightshades pass, a silencer, and 1000 credits. Choosing the credits is the best, because it allows you to buy both the silencer (500 credits) and the Nightshades pass (500 credits).