Seven men were arrested Tuesday for their alleged involvement in the April theft of some ¥380 million ($3.3 million) in cash in Fukuoka, police said.
The men, aged 25 to 52, are suspected of stealing a bag containing the cash from an employee of a Tokyo precious metal shop who had come to the prefecture to buy gold, police said.
The attack took place at a parking lot near a Mizuho Bank branch at around 12:25 p.m. on April 20, the police said, adding that the victim had been sprayed with an unidentified substance.
The heist amounted to the fourth-largest ever in Japan in terms of value, the National Police Agency said.
Among the suspects are Yoshiaki Tobo, 44, and Keita Hirai, 25. Police believe the two were the ringleaders in the robbery.
Authorities believe there could be linked to a major crime group and the seven suspects have connections to Tokyo.
Police also arrested two other men — including Yusuke Fujimoto, 29, an employee of a used car dealership — on charges of attempting to destroy evidence by supplying a getaway vehicle on April 22.
The suspects are believed to have already known when the cash would be withdrawn, investigative sources said, adding that on the previous day, the victim was in Fukuoka for gold transactions and withdrew almost the same amount of cash.