Complex sentence: The publication of the men's letters containing eloquent professions of innocence intensified belief in their wrongful execution, yet further ballistics tests and incriminating statements by the men's acquaintances have clouded the case.
Split into simpler sentences: The publication of the men's letters, containing eloquent professions of innocence, intensified belief in their wrongful execution. Additional ballistics tests and incriminating statements by the men's acquaintances have clouded the case.