[sǐ wú duì zhèng]   

死    无    对    证    对证：核实。当事人已死，无法核对事实。

死无对证，成语，指当事人已死，无法核对事实。

There was no testimony of witness after the conspirator passed away

死声咷气    死求百赖    死记硬背    死骨更肉    死心落地