Warren Nolan was a decorated combat veteran and marksman sniper. After Ballard's election, he became his chief of security and worked with him on his anti-crime campaign. He also guided Tanner throughout the campaign, giving him targets and information.
During the campaign, Tanner captured Lena Robins in the street after a chase. Before she could give him any information on Ballard, she was killed by a sniper. Tanner was subsequently blamed for the murder.
Tanner eventually tracked Nolan down to a junk yard and met him there with Lena Robins's Prototype Armored Car. After a chase, Tanner destroyed Nolan's car at a turnpike.
Nearly dead and bribed with Ramsey's painkillers, Nolan revealed to Tanner Ballard's plans to leave the country. Tanner left Nolan to die on the turnpike after giving him a bag of painkillers (which were actually breath mints.) His pleas for help were ignored.
Later, the NYPD found Nolan's body along with the sniper rifle used to kill Lena in his trunk. Thus, her murder was pinned on Nolan.
Nolan drives two cars throughout the game. He is mostly seen driving his fictional KODACHI XenoWheel. In the last mission he appears in, he is driving the fictional SARTACUS Heavy Bear Turbo. Both of these can be unlocked during the course of the game.