Why one should not touch the back side of ( prushta )Temple ?.

Why one should not touch
the back side of ( prushta ) the Temple ?.

When doing Pradakshina (Circumbulation) to the God in the temple,
 one should not touch the back side of the temple. There the
Raakshasas (demons)  stay.  Hence one must not touch while doing
Pradakshinas. And do the Pranam (Salutation) away from that part
without touching.