Li Xiangjun (a pseudonym), a 15-year-old boy who had been arrested for stealing a mobile phone, did not know what to think when Xu Ting approached him at the police station and introduced himself as Li's "appropriate adult".

Nor could he have known that Xu, a social worker, would help him turn his life around.

"He was very friendly with me, and when saw him, I instinctively knew he would help me work past my past sins," Li said, now 17.