My heart goes to the parent of William Yau. May your child rest in peace.
I have a 6 year old son too, hope who ever did this to your son is caught and receive severe punishment. Malaysia have quite a number of missing children and not even one kidnapper is caught. This is something you need to ponder. It is indeed worries and saddens you to think that these criminals are still at large.
Just pray to Allah, may our children be protected from all these. Ameen.