To convict someone of such a serious charge, the prosecution must prove their case beyond a reasonable doubt.

convict 是动词，由前缀 con-（表示"完全、共同"）和词根 vict（来自拉丁语 vincere，意为"征服"）组成，原意是"完全征服"，引申为"证明有罪、定罪"的意思。在法律语境中，指通过法律程序正式判定某人有罪。