A former SoftBank Corp. employee was indicted Friday on a charge of illegally acquiring corporate secrets, a violation of the law on preventing unfair competition, prosecutors said.
Yutaka Araki, 48, allegedly obtained the proprietary information from a SoftBank server on Feb. 18 last year and gave it to a Russian diplomat in Japan.
Araki, who was arrested in January, has admitted to receiving money in exchange for the digital information, investigators said.
Going through the Foreign Ministry, the police asked the Russian Embassy to present Anton Kalnin, the second-highest official at the Trade Representation of the Russian Federation in Japan, and another official they suspect was involved in the theft.
But Kalnin left for Russia on Monday. The other official had returned to Russia in 2017.
SoftBank, a unit of SoftBank Group Corp., has said the leaked information was "low in confidentiality" and related to manuals for mobile phone base stations and other communications facilities.
The mobile carrier fired Araki in December.