Final answer:
Roy Bryant and J. W. Milam were found not guilty of Emmett Till's murder but later admitted to the crime. Due to double jeopardy protection, they could not be retried or found guilty again.
Step-by-step explanation:
The murderers of Emmett Till, Roy Bryant, and J. W. Milam, were initially found not guilty by an all-white jury. However, in a later interview, both defendants admitted to abducting and killing Till. Due to the constitutional protection of double jeopardy, they were not able to be retried or found guilty again. Therefore, the final verdict was not guilty, although the evidence clearly pointed to their guilt.