Japan’s national broadcaster NHK says a Korean-Japanese man in Japanese police custody has confessed to working as a spy for North Korea in South Korea.

The man, identified only by his surname Ahn, reportedly told police that he made contacts with high-level South Korean officials, including lawmakers and government officials, for North Korea.

As evidence that Ahn worked as a spy for the North, Japanese police have revealed a passport issued to him by North Korea, a business card stating him as a representative for a North Korean trading company, and a certificate of travel issued by Seoul.

Ahn was arrested last month on charges of illegally exporting three high-end cars to the North after getting orders from a spy agency in the communist nation.

Police are now focusing on finding out who aided Ahn in his undercover activities.