The Da Vinci Code

Jacques SauniÃ¨re (Jean-Pierre Marielle), the Louvreâs curator, is pursued through the Great Gallery by an albino Catholic monk named Silas (Paul Bettany), who demands the location of the Prioryâs âkeystoneâ to find and destroy the Holy Grail. SauniÃ¨re gives him a false lead and is murdered, the police finding his body posed like the Vitruvian Man. Police captain Bezu Fache (Jean Reno) summons American symbologist Robert Langdon (Tom Hanks) to examine SauniÃ¨reâs body. Langdon discovers a message hidden by blacklight which contains an out of order Fibonacci number sequence. A police cryptographer and SauniÃ¨reâs granddaughter, Sophie Neveu (Audrey Tautou), reveals to Langdon that Fache planted a tracker on him, believing he murdered SauniÃ¨re due to a message to find him, erased by Fache. The two get rid of the tracker and sneak around the Louvre, finding more clues in Leonardo da Vinciâs works, Langdon deducing that SauniÃ¨re was grand master of the Priory of Sion.
Silas is revealed to be working for an anonymous person named the Teacher, alongside members of Opus Dei led by Bishop Aringarosa (Alfred Molina). Evading the police, Langdon and Sophie travel to the Depository Bank of Zurich, discovering a safety deposit box opened by the Fibonacci sequence. Inside is a cryptex: a cylindrical container that hides a papyrus message which can only be accessed by spelling out a five-letter code word using dials. When the police arrive, Langdon and Sophie are aided by the bank manager Andre Vernet (JÃ¼rgen Prochnow), only for him to take them hostage in the back of a truck, demanding the cryptex. Langdon disarms Vernet, and he flees with Sophie.
The two visit Langdonâs friend Sir Leigh Teabing (Ian McKellen), a Holy Grail expert, who claims the Grail is not a cup but instead Mary Magdalene, who was Jesus Christâs wife and pregnant during His Crucifixtion, and the Priory was formed to protect their descendants. The Opus Dei have been trying to destroy the Grail to preserve the credibility of the Vatican. Silas breaks in, but Teabing knocks him out. The group escape to London via Teabingâs private plane, aided by his butler Remy Jean (Jean-Yves Berteloot). They travel to the Temple Church but the clue to unlocking the cryptex is a red herring. Silas is freed by Remy, who claims to be the Teacher, taking Teabing hostage and dumping him in his carâs trunk while Silas hides out in an Opus Dei safe house. Teabing poisons Remy and send the police after Silas, who is shot by police after accidentally wounding Aringarosa, who is promptly arrested by Fache for using him to hunt Langdon.
Langdon and Sophie are confronted by Teabing, revealed to be the Teacher, who wants to bring down the Church for centuries of persecution and deceit. The trio goes to Westminster Abbey to the tomb of Isaac Newton, a former grand master of the Priory. Langdon tosses the cryptex into the air, Teabing catching it but the papyrus is destroyed. The police arrive to arrest Teabing, but he realizes Langdon removed and solved the cryptexâs code beforehand. The code is revealed to be âappleâ after Newtonâs gravity-based discovery and the clue leads Langdon and Sophie to Rosslyn Chapel in Scotland.
Inside, they discover Magdaleneâs tomb has been removed. Langdon realizes that Sophieâs family died in a car crash, but the media reported she too died. SauniÃ¨re was not her actual grandfather but her protector, and she is the last descendant of Jesus Christ. The two are greeted by several members of the Priory, including Sophieâs grandmother, who promise to protect her. Langdon and Sophie part ways, the latter returning to Paris. Whilst shaving, he cuts himself and has an epiphany when his blood curves down the sink, reminding him of the Rose Line. He follows the line to the Louvre, discovering the Holy Grail is hidden beneath its iconic pyramid and kneels before it like the Knights Templar before him.

Question: Why does the police captain summon Robert Langdon to the scene?
Answer: He believes Langdon murdered the victim.