It is often said that a new-born baby can be murdered very easily by passing a needle through the anterior fontanel, causing fatal brain damage. In such a young child, the hole closes very quickly and, supposedly, leaves no trace.
During the times of witch hunts, this was an accusation frequently levelled at supposed witches who worked as midwives. Since infant mortality was so high in such times, it was easy to make such accusations without need for any real evidence - ideal for the time. Whether such practice ever really did take place is uncertain.