whom helped Jack fake his death. Michelle is killed when her car explodes and Tony is critically injured in a secondary explosion but Jack manages to save Chloe. After investigating David Palmer's death, Jack goes looking for further information at LA/Ontario International Airport, which is subsequently attacked by terrorists. The terrorists are Russian separatists being coordinated by a former CIA officer named James Nathanson. They take 40 people hostage in an attempt to dissuade President Logan from signing a landmark anti-terrorism treaty with Russian President Yuri Suvarov. Terrorists, led by Vladimir Bierko, use the plot as a diversion to steal 20 canisters of VX nerve gas. While searching for the nerve gas, Jack discovers the involvement of James Nathanson and White House Chief of Staff Walt Cummings. They plan to release nerve gas on Russian soil and use that as an excuse for invoking the military clauses of the treaty, allowing Logan to secure American petroleum interests in Central Asia. David Palmer was killed because he was beginning to find out about their plan. The terrorists weren't aware of this plot, believing they were being assisted by the American conspirators to smuggle the gas to Moscow, through their base in Asia and use it to attack Moscow in retaliation for Russia not giving the country the terrorists come from their independence and freedom from Russian rule. The nerve gas is deployed at Sunrise Hills Shopping Mall (resulting in 10–20 fatalities out of eight-nine hundred shoppers) and Tyler Memorial Hospital (unsuccessfully due to the actions of CTU and Curtis Manning). Jack questions a former co-worker of his, Christopher Henderson, who he believes is willing to help. Instead, Henderson locks Jack in a room with a bomb, nearly killing him. Jack has Henderson brought to CTU and tortured; however, he refuses to reveal additional knowledge about the conspiracy. When terrorists break into CTU and release nerve gas there, Christopher Henderson, Tony Almeida, Jack Bauer, Kim Bauer, Chloe O'Brian, Audrey Raines and others are spared in sealed safe-rooms. About 40% of the personnel – including Edgar Stiles and Lynn McGill – are killed. When CTU is decontaminated, Jack rushes to the medical room and sees that Henderson apparently killed Tony and escaped. The fallout from this attack convinces the Vice President to absorb CTU into Homeland Security (DHS). CTU and Homeland Security agents race to find the location of the remaining nerve gas