The captain of a North Korean fishing boat that reached deep into South Korean waters last month was revealed to have intentionally crossed south of the de facto inter-Korean maritime border with the intention of defecting.

This is according to the results of a probe into the incident by authorities announced on Wednesday.

The probe showed that the skipper and another sailor were both trying to reach the South, but that the two others aboard had no knowledge of the plan.

The latter were included because of a rule in the North that requires at least three sailors be aboard a fishing boat before it sets out.

The captain and the sailor were successful in their endeavor, choosing to stay in South Korea after their boat reached the east coast town of Samcheok, some 130 kilometers south of the de facto inter-Korean maritime border.

The other two were repatriated to the North at their request.

The captain told authorities that he wanted to escape North Korea due to economic difficulties and family troubles, while the sailor cited potential punishment for watching South Korean films. 

The sailor said he had previously attempted to cross the inter-Korean border on land and link up with an aunt in the South, but was arrested and imprisoned in North Korea.