Japanese police said Tuesday they have asked investigators to probe four military instructors who allegedly leaked sensitive defense technology.
Police suspect the four men _ all naval academy instructors _ leaked classified data to students in violation of a Japan-U.S. security pact, police in Kanagawa prefecture (state) said in a statement sent to prosecutors.
A Kanagawa police spokesman read the statement over the telephone on condition of anonymity, citing department policy. The men's names have not been released as they have not been arrested, he added.
The data involves U.S.-developed technology for Aegis radar systems used on several Japanese destroyers and U.S. warships carrying missile interceptors.
The case surfaced in March, when police found the information on a computer disk in an unrelated investigation.
Police had already asked for an investigation into one of the four instructors last Thursday as part of a separate aspect of the case, police official Yoshinobu Yokota said. He did not elaborate further.
Earlier this month, police arrested another naval officer, Sumitaka Matsuuchi, for allegedly leaking the information in August 2002.
The scandal has been an embarrassment for Japanese defense officials as Tokyo and Washington accelerate their joint missile defense system to counter North Korea's testing of missiles and a nuclear device.
The case has raised concerns about the way Japan's military handles classified information and prompted officials to call for improved intelligence management.