Question: Who played the main characters in Tomas Alfredson's 2008 vampire film?

full_context: Document 1: Vampires vs. Zombies: Vampires vs. Zombies is an independent horror film loosely based upon J. Sheridan Le Fanu's classic 1872 novel "Carmilla". Unlike Le Fanu's story, however, most of the action in the film takes place inside a car. The title and the cover were obviously inspired by the horror film "Freddy vs. Jason", it's unclear if it was intended as a mockbuster of that film or not.
Document 2: Lina Leandersson: Lina Leandersson (born 27 September 1995) is a Swedish actress. She played the lead role of Eli in the 2008 Swedish romantic vampire film "Let the Right One In", based on the novel by the same name. Born in Falun, Leandersson started performing at an early age. She acted in local amateur theatre performances, and had a few brief television appearances in 2006. At the age of eleven, Leandersson was cast to play one of the two leads in Tomas Alfredson's film, "Let the Right One In", after applying for the role through a web-based casting service. The film was an international success, and Leandersson's performance as the vampire Eli brought her widespread critical acclaim as well as several awards and nominations. She has stated that she wants to continue acting.
Document 3: Kaj Steveman: Kaj Steveman (born 1968 in Stockholm) is a Swedish visual effects supervisor. He was the Founder and head of Fido Film, one of Sweden's most prominent special effects studios and is most known for his acclaimed work on the Swedish vampire films Let the Right One In and Frostbite. He was also visual effects supervisor for and Storm and worked as assistant director in the cult film Evil Ed. He worked as a make-up artist on The Hunters.
Document 4: Let the Right One In (film): Let the Right One In (Swedish: "Låt den rätte komma in" ) is a 2008 Swedish romantic horror film directed by Tomas Alfredson, based on the 2004 novel of the same title by John Ajvide Lindqvist, who also wrote the screenplay. The film tells the story of a bullied 12-year-old boy who develops a friendship with a vampire child in Blackeberg, a suburb of Stockholm, in the early 1980s. Alfredson, unconcerned with the horror and vampire conventions, decided to tone down many elements of the novel and focus primarily on the relationship between the two main characters. Selecting the lead actors involved a year-long process with open castings held all over Sweden. In the end, the 11-year-olds Kåre Hedebrant and Lina Leandersson were chosen for the leading roles. They were subsequently commended by both Alfredson and film reviewers for their performances.
Document 5: Vampire (2011 film): Vampire is a 2011 dramatic horror-thriller film that was directed and written by Shunji Iwai. It was first released on January 22, 2011 at the Sundance Film Festival and is the first film he has directed in English. The movie stars Kevin Zegers as a teacher who believes himself to be a blood-drinking vampire.
Document 6: Lasse Hallström: Lars Sven "Lasse" Hallström (] ; born 2 June 1946) is a Swedish film director. He first became known for directing almost all music videos by pop group ABBA, and subsequently became a feature film director. He was nominated for an Academy Award for Best Director for "My Life as a Dog (Mitt liv som hund)" (1985) and later for "The Cider House Rules" (1999). His other celebrated directorial works include "What's Eating Gilbert Grape" (1993) and "Chocolat" (2000).
Document 7: Let Me In (film): Let Me In is a 2010 American-British romantic horror film written and directed by Matt Reeves and starring Kodi Smit-McPhee, Chloë Grace Moretz, Elias Koteas, and Richard Jenkins. It is a remake of the 2008 Swedish film "Let the Right One In" (2008). It tells the story of a bullied 12-year-old boy who develops a friendship with a female child vampire in Los Alamos, New Mexico in the early 1980s.
Document 8: Florian Henckel von Donnersmarck: Florian Maria Georg Christian Graf Henckel von Donnersmarck (born 2 May 1973) is a German film director, best known for writing and directing the 2006 Oscar-winning film "The Lives of Others" and 2010's "The Tourist", starring Angelina Jolie and Johnny Depp.
Document 9: Four Shades of Brown: Four Shades of Brown (Swedish: Fyra nyanser av brunt ) is a 2004 Swedish film written by the comedy group Killinggänget and directed by their member Tomas Alfredson. The film stars Robert Gustafsson, Johan Rheborg, Henrik Schyffert, Jonas Inde, Maria Kulle and Ulf Brunnberg. The film consists four interweaved stories about life tragedies, with settlements related to fatherhood as the common theme. It was produced by Sveriges Television.
Document 10: Daniel Alfredson: Hans Daniel Björn Alfredson (born 23 May 1959 in Stockholm, Sweden) is a Swedish film director who is best known for directing film versions of two parts of the "Millennium Trilogy": "The Girl Who Played with Fire" and "The Girl Who Kicked the Hornets' Nest". At the 29th Guldbagge Awards he won the award for Best Screenplay and was nominated for Best Director for the film "The Man on the Balcony". His latest film is "Blackway" starring Anthony Hopkins, Julia Stiles and Ray Liotta.
Document 11: Tomas Alfredson: Hans Christian Tomas Alfredson (born 1 April 1965) is a Swedish film director who is best known internationally for directing the 2008 vampire film "Let the Right One In" and 2011 espionage film "Tinker Tailor Soldier Spy". Alfredson has received the Guldbagge award for Best Direction twice; in 2005 for "Four Shades of Brown", and in 2008 for "Let the Right One In".
Document 12: Thomas Vinterberg: Thomas Vinterberg (born 19 May 1969) is a Danish film director who, along with Lars von Trier, co-founded the Dogme 95 movement in filmmaking, which established rules for simplifying movie production. He is best known for the films "The Celebration" (1998), "Submarino" (2010), "The Hunt" (2012) and "Far from the Madding Crowd" (2015).
Document 13: Tinker Tailor Soldier Spy (film): Tinker Tailor Soldier Spy is a 2011 Cold War espionage film directed by Tomas Alfredson. The screenplay was written by Bridget O'Connor and Peter Straughan, based on John le Carré's 1974 novel of the same name. The film, starring Gary Oldman as George Smiley, along with Colin Firth, Tom Hardy, John Hurt, Toby Jones, Mark Strong, Benedict Cumberbatch, and Ciarán Hinds, and featuring David Dencik, is set in London in the early 1970s and follows the hunt for a Soviet double agent at the top of the British secret service.
Document 14: Twilight (2008 film): Twilight is a 2008 American romantic fantasy film based on Stephenie Meyer's popular novel of the same name. Directed by Catherine Hardwicke, the film stars Kristen Stewart and Robert Pattinson. It is the first film in "The Twilight Saga" film series. This film focuses on the development of the relationship between Bella Swan (a teenage girl) and Edward Cullen (a vampire), and the subsequent efforts of Edward and his family to keep Bella safe from a coven of evil vampires.
Document 15: The Girl with the Dragon Tattoo (2011 film): The Girl with the Dragon Tattoo is a 2011 Swedish-American psychological thriller film based on the novel of the same name by Stieg Larsson. This film adaptation was directed by David Fincher and written by Steven Zaillian. Starring Daniel Craig and Rooney Mara, it tells the story of journalist Mikael Blomkvist (Daniel Craig)'s investigation to find out what happened to a woman from a wealthy family who disappeared 40 years prior. He recruits the help of computer hacker Lisbeth Salander (Rooney Mara).
ground_truth: Kåre Hedebrant and Lina Leandersson