The four teenagers arrested after a robbery at a luxury watch shop in Tokyo¡¯s Ginza district earlier this week were sent to prosecutors on Wednesday, with investigators saying the suspects have claimed they don¡¯t know each other.

The Metropolitan Police Department will analyze smartphones used by the suspects ¡ª a 16-year-old, an 18-year-old and two 19-year-olds ¡ª and probe their relationship and how they came together before the Monday robbery.

A group of three masked assailants threatened the shop¡¯s staff with a knife before smashing showcases and placing merchandise into black bags, eventually escaping in a rental car. There were five staff members in the store at the time but no one was injured.

Witnesses said two people were waiting in the car during the incident, leading police to believe that more suspects were involved.

Police discovered the getaway car driving in Tokyo¡¯s Chiyoda Ward, but lost sight of it after a brief chase that saw it pass the National Diet Building and National Diet Library. Police later found it abandoned on a dead-end-street in neighboring Minato Ward, and the suspects were apprehended at a residential building nearby, apparently having changed clothes since the robbery.

Around 30 to 40 watches were found in a bag inside the car, while a black bag containing around 30 watches and two white masks were found near the car. Police are probing the possibility that over 100 watches were taken from the shop.

Investigators said one of the three suspects who entered the store had called out to the others that they had 30 seconds left, with police looking into the possibility that he may have been the leader of the group.

They are also probing the possibility that the suspects became involved in the heist through a yami baito, (¡°dark¡± part-time jobs) posting. Such jobs involve illegal activities performed in exchange for high pay. Some are posted on social media, offering high rewards without providing detailed information about the jobs.

Investigators said all four suspects are residents of Yokohama. The 18-year-old high school student has denied the charges, but the other three suspects have admitted to the allegations.

Details about the 16-year-old suspect will not be made public due to protections under the juvenile law, but the remaining suspects, considered ¡°specified juveniles¡± after a revision to the law last April, could see their details released if they are formally charged over the robbery.

The four suspects are currently facing charges over trespassing at a residential building just before their arrest.

Information from Kyodo added