Two men robbed a jewelry shop in the Ginza shopping district in Tokyo's Chuo Ward of 3.5 billion yen worth of jewelry Friday, police said.
Police said the men entered the Le Supre-Diamant Couture de Maki shop shortly before noon and made off with 12 pieces of jewelry, including a 3 billion yen diamond necklace.
The robbers pretended to be customers before spraying liquid at the store's sales staff and forcing them to lead them to the third floor, where the jewelry was, police said.
One of the store clerks sustained minor injuries.
Investigative sources later said the two men were captured on video by the store's security cameras. Police are analyzing the images and traces of blood that were probably left by one of the robbers, they said.
The robbers smashed the glass showcases with a hammer and took the jewelry, police said. Witnesses said the men appeared to be in their 30s or 40s.