Elena Derevko's name was first mentioned by Jack Bristow in season 3. Throughout the beginning of season 4, Arvin Sloane and Jack Bristow had been investigating her. When we first met Elena, we knew her as Sophia Vargas, a Argentine woman who ran an orphanage in the 80's which housed Arvin Sloane and Irina Derevko's love child, Nadia Santos. At the time when Jack and Arvin were investigating Elena, she was residing in Lisbon, Portugal. One of the first members of the alias team to make contact with Elena was Michael Vaughn. At the time, Elena was making Vaughn believe that his father was not killed by Irina Derevko and that he is still alive. This was not true as Sydney and Michael soon discovered after a thorough investigation. One day Nadia Santos received a phone call from Elena saying that her house had been robbed and that she had been assaulted. Nadia decided to let Elena stay with her and Sydney in Sydney's house. Elena took advantage of this nowing that she was trusted by Nadia as the woman who gave her a home at a young age. During this time Jack and Arvin revealed to Nadia and Sydney that Elena had been tracking and spying on them for the last decade. They were shocked to find photos of them at a young age, high school transcripts, nothing that Elena Derevko should have her hands on. While Elena was staying with Nadia, she hacked into her APO laptop and authourised that alarms and security systems be disengaged so that herself and team could infiltrate DSR facilities and steal priceless Rambaldi artifacts. One night she authourised that the security system of a DSR facility in Los Angeles to be shut down so a team could infiltrate this facility and steal Nightengale. On this night Sophia left Nadia's house to go to a hotel, after she left a CIA team and director came to her house looking for Nadia to take her into custody. This is when the CIA and Nadia learnt that Sophia Vargas was an alias and that her real name was Elena Derevko. During this time Elena was on the run, she was hiding in Prague. Soon after this Arvin Sloane left APO to go join Elena in her quest for world domination. At this time Elena had her sister Irina in custody. Irina was being held in a prison camp in Tikal, Guatamala. Sydney, Jack and Nadia infiltrated this prison camp and rescued Irina. After this Elena had moved to the Russian city of Sovogda where she contaminated the drinking water so she would have the city in her control. Over the city she had a massive Mueller Device which coinsidered with the contaminated water and sent the residents of Sovogda crazy. An APO team and Irina Derevko went to Sovogda to shut down her operation. As a result Nadia was infected by the virus. Irina and Jack interogated Elena to find out if Sydney cut the Yellow or Black wire to shut down the device. The wires turned out to be blue and white. Jack threatened to infect her with the virus unless she told them which wire to cut. Jack put the syringe into her and just before infecting her she said tell Sydney to cut the white wire. Straight away Irina shot Elena in the head killing her. Irina then radioed Sydney telling her to cut the blue wire.