A North Korean nuclear scientist deported back to his home country after defecting to China has reportedly committed suicide in his prison cell hours before he was due to be interrogated.

The defector, who is in his 50s, was a lead researcher in the physics centre of the State Academy of Sciences in Pyongyang. He was identified by Radio Free Asia as Hyun Cheol-huh, although it is not known if this was his real name.

A source in North Hamgyong province told RFA that he was forced back on November 17 and placed in solitary confinement at the state security department in Sinuiju city, where he consumed poison.

“He died before he could be questioned about the reasons for his escape, who had helped him and what his route had been,” he said.

Mr Hyun is said to have taken leave from his job “because he was showing signs of anxiety over his research projects,” added the source.

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