Scriptural source for the lost son story

I vaguely recall reading this story before, possible from the Suttas. Can anyone tell me the scriptural source? (Not looking for modern re-telling such as those by Ven Thich Nhat Hanh.) > THE LOST SON > > "A young widower, who loved his five year old son very much, was away > on business when bandits came who burned down the whole village and > took his son away. When the man returned, he saw the ruins and > panicked. The took the burnt corpse of an infant to be his son and > cried uncontrollably. He organised a cremation ceremony, collected the > ashes and put them in a beautiful little bag which he always kept with > him. Soon afterwards, his real son escaped from the bandits and found > his way home. He arrived at his father's new cottage at midnight and > knocked at the door. The father, still grieving asked: "Who is it?" > The child answered, it is me papa, open the door!" But in his agitated > state of mind, convinced his son was dead, the father thought that > some young boy was making fun of him. He shouted: "Go away" and > continued to cry. After some time, the child left. Father and son > never saw each other again." After this story, the Buddha said: > "Sometime, somewhere, you take something to be the truth. If you cling > to it so much, even when the truth comes in person and knocks on your > door, you will not open it." > (http://viewonbuddhism.org/resources/buddhist_stories.html)