That’s not how it works in America. Investigators are supposed to look for evidence that a crime was committed, and, if they don’t find enough to contend that a crime was a committed, they are supposed to say “We didn’t find enough to contend that a crime was committed.” They are not supposed to look for evidence that a crime was not committed and then say, “We couldn’t find evidence of innocence.” Obviously this (stupidly or intentionally) leaves out the case where investigators look for evidence that a crime was committed and they do find such evidence. That's what happened here.