Imagine a fifty year old would come to the police and tell them that forty years ago when he was ten his next door neighbor John Doe tried to poison him. John gave him a bottle of soda and he drank it. After he drank it he fell down feeling extremely ill while John taunted him saying that it was poisoned. The boy was unconscious and vomiting for hours until he gradually over several days recovered. The boy never went to a doctor or called the police or told anyone about what had happened because he was afraid of revenge from John Doe. Now that he has gotten older and summoned up the courage to turn John Doe in. John Doe, a well respected elderly family man with no prior criminal record, vehemently denies it. There is no other evidence of his guilt
Would John Doe end up convicted? Not in any fair court.
OTOH if instead of poison soda, the crime was molestation, (assuming no statute of limitations)then John Doe stands a very high chance of conviction with a sentence on par with a murderer. Why is that exactly?