A North Korean IT engineer based in China has received remuneration for developing a smartphone application for a Japanese company while using the name of a South Korean national living in Japan, police said Wednesday.

The 57-year-old South Korean man who allowed the IT engineer to use his name, and a 75-year-old female relative of the engineer who acted as an intermediary for the transfer of funds, were referred to prosecutors by the police on Wednesday on suspicion of violating Japan's banking law.

The United States and other governments have warned that North Korea is earning foreign currency by having its IT staff work abroad. The Japanese police said they will investigate the possibility that the IT engineer sent some funds back to North Korea.

The South Korean man, a resident of Yokohama, is suspected of deducting a fee from the approximately 1.91 million yen ($15,000) paid by the Japanese company for the app and transferring the remainder to a bank account of the female relative in June 2019.

The IT engineer was then able to withdraw the funds in Chinese yuan using a debit card connected to the account.

The relative, who resides in Tokyo, is suspected of being an accomplice to the crime by lending her card to the IT engineer. Both have admitted to the charges, according to investigators.

The North Korean IT engineer used the name of the South Korean man to register with a Japanese service that matches clients with freelancers, developing several apps by June 2019, the police said.

The South Korean man claims he met the IT engineer while visiting the North Korean capital Pyongyang on business, they said.