(a) Offense defined.--A person who obtains property upon agreement, or subject to a known legal obligation, to make specified payments or other disposition, whether from such property or its proceeds or from his own property to be reserved in equivalent amount, is guilty of theft if he intentionally deals with the property obtained as his own and fails to make the required payment or disposition. The foregoing applies notwithstanding that it may be impossible to identify particular property as belonging to the victim at the time of the failure of the actor to make the required payment or disposition.

(b) Presumptions.--An officer or employee of the government or of a financial institution is presumed: