He deduces Gabriel's next target is the power grid, so they drive to a utility superstation in West Virginia. They find the superstation under control by a team led by Linh. McClane kills all but Linh. After an intense, violent struggle between the two, Linh, trapped in a car, is killed when the vehicle falls down an elevator shaft. While Farrell is working on the hub computer to slow down the damage done, he is able to trace Gabriel and uploads his picture. He then sends it to Bowman at the FBI. McClane is shocked to learn that Bowman and Gabriel once worked together at the U.S. Department of Defense. Gabriel was the chief programmer for infrastructural security. He warned the department of weaknesses that made America's network infrastructure vulnerable to cyberwarfare, but he was ignored and his unorthodox methods got him fired, and he is out for revenge. Enraged over Linh's death, Gabriel redirects large amounts of natural gas to the superstation to kill McClane and Farrell, and they barely escape. McClane and Farrell then travel by helicopter to the home of super hacker, Frederick "Warlock" Kaludis in Baltimore. Warlock identifies the piece of code Farrell wrote for Linh as a means to access data at a Social Security Administration building at Woodlawn, Maryland. He confirms Gabriel's former ties as a government employee. Doing a traceroute, Warlock locates Gabriel. The Woodlawn building is actually an NSA facility intended to back up the nation's personal and financial records in the event of a cyber attack and designed by Gabriel himself. The attack on the FBI triggered a download of financial data to Woodlawn, data which Gabriel plans to steal. Meanwhile, ordered by Gabriel, one of his top men kills all but one of his computer hackers after they've outlived their usefulness. Gabriel then taps into the connection they made, which reveals the location of McClane's estranged daughter Lucy, whom he kidnaps. McClane and Gabriel then meet - virtually - McClane telling him he will lose. McClane and Farrell race to the Woodlawn facility. Farrell finds the facility's main server and encrypts the data Gabriel's men downloaded before getting captured. Gabriel then takes Farrell and Lucy with him as he flees. McClane pursues them, hijacking their semi mobile base. Accessing the communication system of an F-35B Lightning II, Gabriel orders the pilot to attack the truck McClane is driving, but the