'Malicious allegations are rare'...Rare maybe but not that rare as to be discounted: ask some teachers who have been wrongly accused of child abuse by a vindictive child. Even when found quite innocent, the cloud hangs over the teacher forever. Threats of being reported to Childline for no good reason are not unheard of. Then we must consider false memory syndrome: patients under therapy 'remembering' incidences of abuse as a child which certainly did not occur but were planted, perhaps unwittingly, in the patients' mind by the therapist. Then there's jumping on the bandwagon to make a fast buck.
By all means listen to the child but with a critical ear. Children are not always sweet innocents: they can be vindictive liars too.
Not that the above is relevant to the current case.