A Tokyo-based trading house specializing in exports to Iran may have been involved in illegal shipments of weapons parts to Tehran, for which executives of another trading firm were arrested Wednesday, police sources said Thursday. Two former executives of the defunct Tokyo-based firm Sun Beam K.K. were arrested on suspicion of illegally exporting parts for antitank rocket launchers to Iran. On Thursday, the Iranian Embassy released a statement denying any involvement in the case. Police identified the suspects as Ichiro Takahashi, 63, of Yokohama, and Tsuneo Ishida, 67, of Kawagoe, Saitama Prefecture. Both carried the title of representative director of Sun Beam, a two-man firm. Investigators believe another Tokyo-based trading house, which was not named, was a go-between for Sun Beam and Iran Electronics Industries, an Iranian state-run contractor. The unnamed trading house, established in Tokyo's Shinagawa Ward in February 1988, currently has its office in neighboring Minato Ward. All of its executives are Iranians. Takahashi is believed to have frequently visited the company, and investigators are looking into its involvement in the illegal shipping by searching the office and questioning the officials.