circumstantial
/ˌsɜ:kəmˈstænʃl; ˌsəkəm`stænʃəl/ adj
1 (of a description) giving full details （指描述）详细的.
2 (of evidence) consisting of details that strongly suggest sth but do not prove it （指证据）有充分细节却无法证实的
You can't convict a man of a crime on circumstantial evidence alone. 不能只靠旁证就判定一个人有罪.