Is witnesses and evidence.
Witnesses are those who do not work for the court because they will not profit at all by the outcome of the court proceeding whether guilt or innocent is established or not.
Evidence is written testimony about what happen, finger prints, DNA ie saliva, blood, skin, bone, semen, urine, fecal matter and the corpse or body.
In felony cases a true conviction needs all of these requirements satisfied.
There must be at thre judges present in the courtroom, a jury and members of the community who do not work for the court directly,except as tax paying citizens, not fugitives.