Alex Krycek moved into the role of Mulder's partner with the unexplained murders of former Vietnam veterans . We discovered, however, that Krycek had a hidden agenda, he was working for the Cigarette Smoking Man. With the disappearance of Dana Scully and the re-opening of the X Files, Krycek himself disappeared. He reappeared to murder Mulder's father, attempted to kill  Mulder himself, was present at Melissa Scully’s murder, but was able to make his escape after an attempt by other lackeys of Cigarette- Smoking Man to eliminate him. Krycek was trapped in a missile silo in North Dakota until he reappeared in ‘Tunguska’. Krycek lost his left arm at the end of ‘Tunguska’. He was seen next in 'Patient X' where he had a brief steamy affair with Marita Covarrubias. As it turned out, however, she betrayed him, only being interested in kidnapping Krycek’s hostage, a Russian boy who was a survivor of an alien resistance fighter attack. Krycek was then forced by the Well Manicured Man to hand over a Russian-made vaccine against the black oil alien to the Syndicate. In ‘The Red and the Black’ Krycek visits Mulder, but instead of killing him although he has the chance, he gives him the name of an air force base where an alien rebel spaceship has crashed and one of the resistance fighters is held captive. Then he gives him a Russian kiss of friendship on the cheek and leaves a totally bewildered Mulder. In ’The End’ Krycek seems now to be working for the Well Manicured Man. He even suggests killing the Cigarette-Smoking Man, however the Well Manicured Man does not allow it, stating that they ‘might need him in the future.’ After the Well Manicured Man is apparently killed in 'Fight the Future', Krycek reappears, his position in the syndicate stronger than ever, in 'Two Fathers / One Son'. He oversees Spender when he is sent by the CSM to kill one of the faceless rebel aliens that has infiltrated the group and when Spender is unable to perform this task, he does the kill for him. He also lets Spender in on the truth about the CSM and his mother Cassandra and their role in the 'project'. He clearly seems to follow an agenda of his own here, too. He fails, however, to prevent the alien fetus from falling into the hands of the faceless aliens.