Police arrested a 31-year-old man and put another man on the wanted list Wednesday in connection with the biggest cash robbery in the nation's history.
Hideaki Ueki was arrested on suspicion of burglary and inflicting bodily harm in the record-setting heist in Tachikawa, western Tokyo, on May 12, the police said.
The other suspect was identified as Yutaka Watanabe, 41.
The police said earlier both are likely to have links with organized crime.
Ueki was arrested in Hino, Tokyo, at his parents' house, which police searched.
They said two men broke into the security company office in Tachikawa and got away with ¥604 million in cash.
The previous record was ¥542.5 million taken in a robbery at a transportation company in Tochigi Prefecture in October 2004.
According to the police, the two suspects in the May 12 robbery entered the office wearing masks at around 3 a.m., beat a security guard with an iron pipe, tied him up with adhesive tape, forced him to reveal the code for a vault and made off with the cash in 70 bags.
The 36-year-old guard was badly wounded.
Based on video footage from a security camera in the office, the police believe they made their getaway by car with Watanabe at the wheel.
They are believed to have switched to another car and took the Chuo Expressway through Tokyo and got on the Joban Expressway in Ibaraki Prefecture, according to the video footage.
The two appear to have entered the security company office through a shower room window, whose lock has been broken for more than half a year. The police suspect that people who know the office very well were involved in the robbery.
Around 10 people, including the two suspects who actually pulled off the heist, may be involved.