Hu Xinyu, a 15-year-old boy who went missing from a high school in Yanshan county, Jiangxi province, in October committed suicide, leaving thoughts of ending his life on a digital voice recorder before doing so, local police said on Thursday. 

Hu Mansong, deputy director of Jiangxi Public Security Bureau and head of the investigation team, said Hu Xinyu hanged himself with shoelaces from a tree in the woods around a grain depot near the school. There were no signs of struggle at the scene, and the possibility of homicide was ruled out after the autopsy results were released.

Hu Xinyu, who attended Zhiyuan Senior High School, was reported missing on Oct 14. According to video footage provided by the school, he was last seen at 5:48 pm in the school's dormitories. His highly decomposed body was discovered by a grain depot employee on Saturday, more than 100 days after he disappeared. 

In the digital voice recorder found near his body, Hu made two recordings — one at 5:40 pm and the other at 11:08 pm — on Oct 14. It appears that he made both recordings while attempting to take his life, Hu Mansong said in a news conference.

"While I am really standing up here, I am starting to become nervous. My heart is pounding. What would happen if I really jumped?" Hu Mansong quoted Hu Xinyu as saying when he tried to jump from the fifth floor of the dormitories during the early evening attempt.

In another attempt later that night, Hu Xinyu was quoted as saying: "It's all meaningless. It's almost midnight and I will just wait a bit to die. My mind has become clouded today and I just want to die now. I feel it's all meaningless."

It's believed that he had developed mental problems after feeling stressed about his life at the school. He also had trouble sleeping and suffered from memory loss, Hu Mansong said.

Hu's disappearance became a high-profile case in China. After his body was found and identified at a site only 400 meters away from the dormitories, people began questioning why the police had failed to find him sooner.

Hu Mansong said the police searched the grain depot four times in October and November but failed to thoroughly search the surrounding woods. 

Police have learned a lesson from the mistake, he added.