On Monday, however, the Miami-Dade state attorney's office dropped all charges against Ajuste, who investigators believe played some role in the events leading up to the Walker shooting. "We determined that that individual was not involved as a shooter in this case," said Assistant State Attorney Abbe Rifkin, the lead prosecutor on the case. "At this time, we are still investigating what his involvement, if any, was. However, we are not looking at him as a suspect in that shooting at all."

Whether the "some role" remark is simply face-saving remains to be seen. If there were any evidence that Ajuste played a role in the shooting, it's unlikely he would have been released.

Wrongful convictions start with a wrongful arrest. It's fortunate for Ajuste that the police investigation did not end (as they too often do) with the unwarranted conclusions drawn by the officers who arrested him. Mistakes like that cause one to wonder whether the case against the newly arrested suspect is built on better evidence, or simply on a desire to arrest someone, anyone, for a cop killing.