What is the ruling if one witness testifies that the killing occurred, and another testifies that the accused confessed to the killing?

Primary text

The killing is established. This is the stated position of Ahmad and chosen by Abu Bakr. The rationale is that the act confessed to by the accused is the same act testified to by the witness, meaning there is no contradiction between their testimonies, and thus the killing is established by their combined witness, similar to when one testifies to intentional killing and the other to accidental killing, or when one testifies the accused owes a thousand and the other testifies the accused confessed to owing a thousand.