For torture to extract a confession, it is difficult for the suspect to prove that he was tortured to extract a confession, because he cannot contact the outside world during detention; after a few months of detention, the case handling agency may say that he was injured outside, and there was no torture during the handling of the case. The act of coercing a confession.
Therefore, an effective way is to entrust a lawyer to provide legal help. Generally speaking, the lawyer's intervention can effectively protect the legitimate rights and interests of criminal suspects. The case-handling agency may also take this into consideration when extorting confessions through torture, that is, whether the lawyer will collect evidence by making transcripts, recording, taking photos, and videotaping. Once the evidence is solidified and charges are laid, the relevant investigators will be held accountable.
However, given the current national conditions, it is inconvenient for local lawyers to offend the local police. If there are clues indicating torture, you can entrust an out-of-town lawyer to provide legal help and file charges.