Dr. Josef Vlachko is a Russian doctor who was the creator of Project Nightingale.

Before Season 4[]

Josef was recruited into DARPA when he vanished 25 years ago after experimenting with human subjects. When he left, he took all the information involving Nightingale with him. Josef eventually contacted Hans Dietrich, a German money launderer, who funded several millions of dollars into Project Nightingale.

Season 4[]

Josef brought Hans into the Yakutia Nuclear Power Plant to show him the true power of Nightingale. After he had his guards haul a Prisoner into one of the testing chambers, Josef activated the tesla coil and unleashed the power of Nightingale. Hans was revolted and amazed by the results, as he witnessed the prisoner's flesh slowly boil and melt off his bones.

After recovering information from Hans, Jack, Vaughn and Sydney go to Siberia and infiltrate the power plant to recover Nightingale. While there, Jack splits away from the group to go find Josef while Vaugh and Sydney go into the security room. As Jack finds Josef, he commands him to sit down and shuts down the security. As he unlocked the doors to the tesla coil, Jack begins to interrogate Josef, demanding to know the location of Elena Derevko. Even after getting shot in the leg, Josef screams he doesn't know anything. Jack was about to interrogate the doctor some more, but Sydney was locked inside the testing chamber and seconds away from dying. He suddenly kills Josef and runs off to go help Sydney, despite the fact Josef may have known more about Elena.