Several masked assailants broke into a luxury watch store in the capital's upscale Ginza district at around 6:30 p.m. on Monday. They threatened to kill the sales clerks with a knife, and are believed to have used crowbars to break into the showcases.
The thieves are thought to have stuffed more than 100 wristwatches into black bags before taking off in a car.
Later that night, police arrested four boys aged between 16 and 19 in the Akasaka district nearby Ginza. They are suspected of trespassing at a condominium close to where police found the vehicle used in the robbery.
Sources say a bag containing about 30 watches was also discovered nearby. Police are investigating whether they were taken from the store in Ginza.
Investigators say three of the boys have admitted to trespassing. The suspects reportedly say they don't know each other.
Thieves take their time
The shocking robbery took place just before sundown. Typically, smash-and-grabs take two to three minutes, but the thieves in Ginza were extremely brazen.
The assailants committed their crime over the course of about 10 minutes as stunned passersby looked on. Some witnesses recorded the incident on their smartphones.
Police believe the getaway car was rented. The license plates belong to another vehicle registered in Saitama Prefecture, near Tokyo.
Investigators also say they found white masks near the abandoned car.
Luxury goods under siege
The robbery is the latest in a series to recently rock Tokyo's downtown areas.
On Sunday, a man ran off with jewelry from a store in the Ueno district. It was the third such crime in the area in three months.
And in the upscale Omotesando district on April 29, three people made off with cash and rings from an accessory shop.
In total, there have now been 11 similar cases in the capital since February. And many involved luxury watches and high-end brand items.