A North Korean nuclear scientist who defected to China has committed suicide after being sent home. The defector, who was part of a group of his countrymen detained in the city of Shenyang on 4 November, reportedly took poison in a state security cell while awaiting interrogation.

According to Radio Free Asia (RFA), he was a lead researcher in the physics centre of the State Academy of Sciences in Pyongyang. He was sent back to North Korea on 17 November, according to a source in North Hamgyong province.

"He killed himself only a few hours after he was placed in solitary confinement at the State Security Department in Sinuiju city" just across the border from China, the anonymous source told RFA.

The source continued: "He died before he could be questioned about the reasons for his escape, who had helped him, and what his route had been.

"He must have been searched many times while being taken from China to Sinuiju, so it's a mystery how he was able to conceal the poison he took."

The source claimed the defector, who was identified as Hyun Cheol Huh, had recently taken vacation leave from work "because he was showing signs of anxiety over his research projects".

"Suddenly, he visited relatives near the border without letting his family know and without carrying valid documents for travel," the source said. "And when he learned that the authorities were looking for him, he simply disappeared."

Kim Jong-un
North Korean leader Kim Jong-Un (R) reacting after the test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location STR/AFP/Getty Images

Security officials are trying to uncover how the defector was able to cross the Tumen river into China and meet up with other defectors, RFA reported.

High-level sources in North Korea identified the defector as Hyun Cheol Huh, in his 50s, but the source told RFA he is unsure if that was his real name. "Generally, State Security will use numbers or fake names when referring to important persons [in their custody]," he noted.

The defector did not tell Chinese police he was a nuclear scientist when he was captured. Authorities were tipped off about the group of defectors by a North Korean state security agent posing as a defector.

"If the Chinese government had known who he was, they would have wanted to learn what he knew and would never have sent him back," the source added.