Gemara:

Bava Kamma,  Makot,  Sanhedrin 

Collections: Rabbi Meth Mini Chabura

References: Makot: 5a ,  Makot: 5b  

Description

Zomemim can exempt themselves by merely contradicting the mazimim (R"Ch), or exempt themselves by claiming access to flying camels (Ramban); still, despite their credibility when espousing these claims, and despite our obligation to make any claim they omit that will save them from death, we do not make these claims for them. Why? Perhaps ordinarily, the zomemim are disbelieved because their silence incriminates them; therefore, our claim on their behalf cannot restore their credibility. However, when they claim innocence on their own, we are deprived of our only reason to disbelieve them more than the latter witnesses, and therefore they are exempt.