A new dramatization of the 2006 poisoning of Alexander Litvinenko shows the former spy, played by David Tennant, helping the police in his final hours.LONDON — In the middle of AMC+’s new dramatization of the poisoning of the intelligence agent Alexander V. Litvinenko, a police officer asks a pathologist about the state of the man’s organs when he died. The doctor thinks for a moment, as though considering how graphic to be, and then replies, “Sludge.”It’s a visceral moment in “Litvinenko,” a limited series written by the “Lupin” creator George Kay that depicts Litvinenko’s 2006 poisoning in London via a cup of tea laced with the radioactive element polonium 210, and its aftermath.While many viewers will remember the photo of Litvinenko on his deathbed, gaunt and newly bald, that appeared on front pages around the world, fewer will know the details of his final days, and how — convinced he was poisoned by President Vladimir V. Putin of Russia — he aided the investigation into the attack, even as his internal organs were failing.The story of a former K.G.B. agent assassinated in broad daylight in the dining room of a British hotel could have made for a sensationalized show about international intrigue. But “Litvinenko,” which comes to AMC+ and Sundance Now on Friday, instead focuses on the human cost behind the headlines.Most of the running time of the series’s four episodes is spent with the police investigating the murder and the Litvinenkos themselves — Alexander (played by David Tennant), but also his widow Marina (Margarita Levieva), who for years agitated for the British government to hold an inquiry into her husband’s death.The police officers investigating the poisoning are featured heavily in the show, including Clive Timmons (Mark Bonnar), center left, and Peter Clarke (Daniel Ryan), second from the left. ITVX/Sundance NowKay’s research for the program involved close collaboration with Marina, as well as the investigating officers, including Brent Hyatt, the London police officer who took 18 hours of statements from Litvinenko in the hospital.That was one way the murder investigation started before anyone had “actually died,” as one of the show’s police officers notes. Litvinenko used the hours it took for the poison to wreck his body “to tell the police what he knew, so he was not just a witness to his own murder, he was a detective in it,” Kay said in a video interview.The first episode covers this time immediately following the poisoning, when every minute was precious. The second shows the weeks following Litvinenko’s death, when the police scrambled to put the pieces together and contain the threat of radiation poisoning to the British public.The subsequent episodes cover the months, and eventually years, that Marina spent fighting for an inquest, and then a public inquiry, into her husband’s death.“We wanted to give a sense of the perseverance of Marina Litvinenko,” Kay said. “She’s the one person who didn’t retire or give up or look the other way, or try and get in the way of the justice. She kept going, and it took her a decade in the end.”“I want people to understand not only what happened to me, to my family, but why it’s happened now to many families,” said Marina Litvinenko, played in the show by Margarita Levieva.ITVX/Sundance NowIn many ways, Marina is the show’s lead character. The widow said she saw cooperating with the show’s creators as her duty.“I want people to understand not only what happened to me, to my family, but why it’s happened now to many families,” she said. Putin’s actions since 2006, including the war in Ukraine, have cost “millions” of people their loved ones, she added.A 2019 play about Litvinenko’s murder, “A Very Expensive Poison,” was written by Lucy Prebble with input from Marina, and there was also a 2021 opera. But this television show arrives after Putin’s invasion of Ukraine, and so in a changed political landscape.Tennant said that the brutal war had been “the moment that the world woke up to Putin, and what he was.” He added: “I think either people didn’t really understand that until now, or they understood it, but it was inconvenient to acknowledge.”In 2006, Britain saw Russia as a supposedly friendly power. At the time the British government condemned Russia’s refusal to extradite Andrei Lugovoi to face trial for the murder in Britain, but in 2013, Home Secretary Theresa May admitted that successive British governments had blocked a public inquiry into the poisoning out of concern for “international relations.”Andrei Lugovoi, whom the British government sought to prosecute for the poisoning, is depicted by Radoslaw Kaim.ITVX/Sundance NowMay eventually agreed to Maria’s long-fought-for public inquiry, which in 2016 found that the poisoning was “probably approved” by Putin.While “Litvinenko” is a show with big political concerns, the persistence of ordinary people is what ultimately motivates it. Tennant said the time he spent with Marina preparing for the role drove that home for him.“The experience of being with her changes it from a story about politics to a story about a family,” he said.Kay also wanted to emphasize Litvinenko’s home life in the show. He “worked in Russian intelligence, but also he loved football and swimming, he was a dad, he got the tube home,” Kay said. “He lives a normal life in all but some aspects of his previous work. And it’s the same with Brent Hyatt.”Hyatt’s home life during the investigation, particularly his struggle to conceive a child with his wife, is brought to the forefront in “Litvinenko.” The show depicts both Hyatt (Neil Maskell) and Litvinenko trying to provide for their families in extraordinary circumstances. In the first episode, before Litvinenko is poisoned, we see his family having dinner and discussing his son’s school homework.“It’s very important to look at the human side of any event,” Marina said. The episodes highlight the work of all the ordinary people who helped her in her pursuit for justice, which was not just motivated by the political import of her husband’s work, but also by her devotion to him as a wife.“I think for some people, it will be a love story,” she said. “When, if you have a real love, you never give up.” More