Rav Zutra bar Tobiah reported that Rav reasoned that disqualified isolated testimony when it prescribes that “at the mouth of one witness he shall not be put to death.” This special admonition against one witness would seem redundant to the earlier context, “At the mouth of two witnesses or three witnesses shall he that is worthy of death be put to death,” so it was taken to mean that individual witnesses who witnesses the crime, one by one, in isolation from each other, were insufficient to convict. Similarly, a Baraita taught that prescribes, “At the mouth of one witness he shall not be put to death,” to cover instances where two persons see the wrongdoer, one from one window and the other from another window, without seeing each other, in which case the evidence could not be joined to form a set of witnesses sufficient to convict. Even if they both witnessed the offence from the same window, one after the other, their testimony could not be joined to form a set of witnesses sufficient to convict.