Carmen in Cambria bar gives you this series of quests.
#1 Slay $5000
Can be found at the top of the map when you enter the Roadblock on the Southern most road South of Estoni, East of Meduma Airport. He is near a building, talk to him and he becomes hostile and can be killed.
#2 Mother of Mayhem $10000
You can find he hanging out in the pit in the Grumm Industrial Sector. Careful as she carries an M79 with rockets.