What constitutes sufficient witness testimony to establish the legal ruling of intentional killing (Qatl)?

Primary text

The establishment of intentional killing through witness testimony necessitates the absolute removal of ambiguity in the witnesses' declaration. The testimony must explicitly state the causal link, such as testifying, "We witness that he struck him and killed him," or, "He struck him, and he died from it." If the testimony is ambiguous, such as stating, "He struck him with the sword and he died," or, "We found him dead afterward," or, "He struck him with the sword, causing his blood to flow, and he died in place," the killing is not established because death might have resulted from another cause following the blow. Sharih rejected testimony where the witness stated the deceased leaned on the accused and died, unless the witness confirmed death resulted directly from that action.