Extrajudicial confession binding only upon confessant, NOT admissible vs. co-accused

The res inter alios rule ordains that the rights of a party cannot be prejudiced by an act, declaration, or omission of another. An extrajudicial confession is binding only upon the confessant and is not admissible against his co-accused. The reason for the rule is that, on a principle of good faith and mutual convenience, a man's own acts are binding upon himself, and are evidence against him. So are his conduct and declarations. Yet it would not only be rightly inconvenient, but also manifestly unjust, that a man should be bound by the acts of mere unauthorized strangers; and if a party ought not to be bound by the acts of strangers, neither ought their acts or conduct be used as evidence against him. [G.R. No. 119005. December 2, 1996]