Teams searched for Song in what police describe as complex terrain and dense vegetation. After not finding any trace of the man, they requested drones from the local police authority to look for a possible hideout from above.
Let our news meet your inbox. The news and stories that matters, delivered weekday mornings.
Shortly after, a drone spotted a blue steel roof on a steep cliff. It also detected household garbage outside what police described as a cave.
When search teams moved in earlier in September, they found "an unkempt old man" in front of the cave and identified him as the elusive Song, who was jailed for trafficking women and children but escaped from prison in 2002.
Police said Song had been living in a cave measuring less than 21 square feet in size, and too small for an average person to stand up in.
Pictures from inside the cave released by police showed blackened cooking pots that appear to have been used to make food over an open fire and what looks like layers of improvised bedding on the cave's floor.
Investigators said the fugitive was living in seclusion for a while and had trouble communicating with the officers.
They said Song has not taken a bath or done laundry in "a long time," and his lifestyle has "devastated" his body. He also cut his own hair, used plastic bottles to get drinking water from a mountain valley and gathered dry tree branches to make fire for cooking.
Song is being sent back to jail, police said.
Yuliya Talmazan is a London-based journalist.
Dawn Liu is a researcher for NBC News based in Beijing.