For 17 years, the whereabouts of the missing child and the identity of the murderer remained unknown, the report said.
It was only in 2018 that police spotted a DNA match between relatives of the dead couple and a boy living in Kaifeng, Henan.
Another police officer, from the Xinyang force, said that an investigation showed the boy had been adopted, which suggested he might have been the child that had gone missing in 2001.
That was confirmed following an interview with the child and further DNA tests, the report said.
The police then turned their attention to the boy's adoptive father, who was identified as a peripatetic doctor called Zhang who worked in rural areas.
Following an investigation, police discovered that Zhang had been working in Shangfengshan around the time the Chen's had been murdered, and with the help of witness statements made him their prime suspect.
The CCTV report said that while under police questioning Zhang confessed to the crime and was subsequently detained.
It did not say when this happened, but said he remained in custody and was awaiting trial.
The report did not identify the teenager, but said that after the arrest of his adoptive father he had gone to live with his blood relatives.
- South China Morning Post