In a way,the problem is that all that is needed is reasonable grounds for suspecting, hence arrest. The grounds may be reasonable at the time but prove to be unsupported by admissible evidence or only a false accusation. It may well prove that some of these accusations are simply false identification, false memories, or unprovable, given the lapse of time and human fallibility.
It's only a problem,' in a way', because the press publish the name of the suspect. They shouldn't. The police don't. Leveson said the press shouldn't. Various senior judges have said the same. But the press doesn't care and will indignantly talk about free speech and the public's right to know. Yet the press only bothers when the suspect is, or was, famous or the case is of exceptional gravity or public interest, such as a child abduction.