One defector, who wanted to be identified only as Kim as he has family members still inside North Korea, told CNN inmates face a slow and painful death. He was sent to a labor camp for a year and a half after being caught crossing into China.

“We received 120 grams of rotten corn for daily food. So many people with the same year and a half sentence as me didn’t survive their term and died of hunger.”

Kim describes seeing many of his fellow inmates die and having to bury them on a nearby hill. The only hill, he said, where flowers grew well due to the large numbers of decaying bodies beneath the ground. “When I went to bury my friend, I found the hole was too small,” he said. “When I asked why, the guy said there was no more room to make a bigger hole. When I dug up the ground with my shovel, I saw about four layers of bodies and human bones.”