Li Hui was first selected to serve as an "appropriate adult" for a juvenile in police detention in May last year.
"He was 17 and had been accused of burglary," Li said of the youth, who was being held by police in northwest Beijing's Changping district. "He was short and thin, and when I saw him for the first time he was silent in a corner."
Inspired by a British program, China introduced the appropriate adult system into Criminal Procedure Law in 2011. It is now being developed in many areas of the country, including Beijing and Shanghai.
As in the UK, which has been running the program since 1984, an appropriate adult supports and advises vulnerable youths being held in custody and aids communication between the youths and police. Appropriate adults can be friends, relatives, teachers, volunteers or social workers.
The British system also covers adults with mental health problems, but the program in China serves only minors younger than 17.
It is usually used when a juvenile's legal guardian is unable or unwilling to attend police interviews and searches, a common situation in Changping, which has a large population of migrant workers.
The district's prosecuting authority said it dealt with 178 criminal cases in 2011, more than 100 of them involving suspects without Beijing hukou, or permanent residency. Of these 100 cases, about 70 percent involved juvenile crime.
"Our district is an urban-rural area and has many migrant workers. They also bring their children, and there are some young people who come to Beijing alone to find jobs," said Yang Furong, director of the juvenile department of Changping's prosecuting authority.
Some parents are busy earning money, leaving the children to take care of themselves. Some parents in remote hometowns cannot afford the travel fees, and even when severe jail sentences are at stake, will be absent when their children are questioned or arraigned, she said.
"The appropriate adult system can solve these problems, and it comforts juvenile suspects," she said. "A few young people whose parents are present during the arraignment may show off in front of those without guardians, which depresses the latter and makes them unwilling to talk with us."
Li's first "client" was from Hubei province, and his parents could not afford to travel to Beijing.
"I simply sat beside him and told him that I'd be accompanying him, instead of his parents. I just tried to keep him calm," he said.
Among the areas piloting the appropriate adult program, Changping district stands apart in that it is the only one that uses legal professionals in the role.
Li, of Cheng Shi Law Firm in Beijing and the legal aid center under Changping district's justice bureau, is one of 127 attorneys from 31 law practices in the district selected to be appropriate adults since the program began in April last year.
"Lawyers may be best suited for this work because they have much more knowledge, so they can make professional suggestions to the young suspects," said Yang Furong.
As an independent party, lawyers can answer suspects' questions about the legal process and supervise the police and public prosecutors' work, making sure that youngsters are treated correctly during interviews, she said.
"Lawyers are the lubricants between the juvenile suspects and the prosecutors," Yang added.
Meanwhile, lawyers can be closer to suspects, because their job is to represent clients and speak for them, the director said, adding that the young suspects' rights will be better protected this way.
Song Lin, another lawyer in the program, said the system is an innovative way to cope with the problems juvenile suspects have, and she hoped it would be extended across the country.
Song said she gave legal advice to a 16-year-old accused of rape by the district's prosecutors in 2011. The teenager did not know what kind of behavior legally constituted rape and asked her a series of questions about the accusation.
"I told him the definition of rape in our Criminal Law and the sentence that he might receive if the charge was confirmed by judges," said the 33-year-old lawyer.
However, some lawyers and experts say this system has a long way to go and needs more legal practice.
Tu Xiaoju, a lawyer specializing in legal aid in the district, said the best appropriate adult would still be a juvenile suspect's parent, and lawyers who are selected should pay attention to what they say during arraignment.
"After all, we're legal workers. We shouldn't be emotional in our work," she said, adding that an appropriate adult should merely give legal advice and supervise prosecutors.
"How to be independent and remain neutral are things each legal professional should think about," she added.
Cao Xuecheng, secretary-general of the Chinese Society for Juvenile Delinquency Prevention Research, the only NGO in the country that specializes in young offenders, said the appropriate adult system still needs exploration.
"At present, parents, teachers, lawyers and even judges can be selected as the appropriate adult. Shanghai prefers to use social workers, and the (Changping) district's prosecuting authority chooses lawyers," he said. "In other words, there's no standard about what kind of people are suitable for the role."
In addition, this new system will need time to fit in with other regulations involving juveniles. "After all, this system isn't independent, it must be used with other articles," he added.