Becoming the first Hollywood studio to take up the mysterious death of former KGB agent Alexander Litvinenko, Warner Bros. has scooped up film rights to a book on the subject for Johnny Depp’s shingle Infinitum Nihil to develop.

As with any Infinitum project, the film about Litvinenko could be a potential starring vehicle for Depp, who has been closely following the story.

Depp will produce with Infinitum prexy Christi Dembrowski and Initial Entertainment Group president Graham King. Infinitum is an Initial Entertainment company.

Unpublished tome “Sasha’s Story: The Life and Death of a Russian Spy” will be penned by New York Times London bureau chief Alan Cowell, who has been covering the story since it first broke in November.

Film rights deal marked the first acquisition for London-based Warner VP of production Ollie Madden, who joined the studio Jan. 1.

In London, the investigation continues into the death of Litvinenko, who was poisoned in late November by polonium-210. Just before his death, he blamed Russian President Vladimir Putin’s regime for the murder. Story has become one of the most mysterious and perplexing crimes of the post-Cold War era, triggering an international investigation led by the U.K.’s top counterterrorism officials.

Cowell, who has reported extensively on British intelligence services, will document Litvinenko’s life and poisoning, as well as address the implications of the case for nuclear proliferation and international terrorism.

Initially, authorities thought Litvinenko was poisoned at a sushi restaurant. Now they believe he may have been poisoned at another location as well.

Cowell will continue covering the story before taking a leave to write the book, which will be published by Doubleday in the U.S. and Transworld in the U.K. later this year. It also has been sold to publishers in France, Holland and Denmark. Inkwell Management’s Michael Carlisle repped English rights.

Other Infinitum/Initial Entertainment projects include “A Long Way Down,” based on the Nick Hornby novel; “Bomb In My Garden”; “Happy Days”; and “Shantaram.” King’s company has a producing deal with Warners.

Depp and Infinitum are repped by UTA.