North Korea releases detained South Korean student 6 months after he was arrested for crossing Chinese border

North Korea has freed a South Korean national who is a student at New York University, in a possible sign it wants better ties with rival Seoul and may back away from a recent threat to launch a long-range rocket later this month.

North Korean state media said it “deported” Joo Won-moon, 21, at the border village of Panmunjom as a “humanitarian” measure about six months after he had been arrested for crossing the Yalu River into the North from the Chinese border city of Dandong on April 22.  It didn’t elaborate.

South Korean officials confirmed Joo’s repatriation. The National Intelligence Service, South Korea’s main spy agency, said it will investigate whether Joo violated the country’s anti-North Korean security law, which prohibits unapproved travel to the North.

Joo has permanent residency status in the United States. The exact motivation for his travel to North Korea wasn’t clear.

North Korea often uses detainees in attempts to win political concessions and aid from rivals Seoul and Washington, and a South Korean analyst said it may have calculated that since Joo’s alleged crime was relatively minor, his release might boost the impoverished, authoritarian country’s international image and lead to more investment and tourism.

Ten days ago, Joo was presented to the media in Pyongyang and said he had not been able to contact his family but wanted them to know he was healthy. For most of the 30-minute appearance, he read a prepared — and probably coached — speech praising the country, its government and people. Other foreigners who have been detained in North Korea have said after their release that they were coached closely on what to say in such statements.