Why was the AFP refused evidence for testing

Schapelle Corby in a written request to the Australian Consul in Bali, asked that the drugs said to be in her possession be forensically tested and a sample be given to the AFP for that purpose. That request was refused by the Bali Police. What was their reason for refusing a request for evidence to be tested? Would they have been embarrassed if the AFP found it was Indonesian weed? How would they have reacted?

Below is the document that lays out the rules for cooperation between Indonesia and Australia in relation to criminal matters. Have a read and see if you can find any reason for refusal by the Bali police for forensic testing.

http://untreaty.un.org/unts/144078_158780/16/7/7481.pdf


4. The Requested State shall promptly inform the Requesting State of a decision of the
Requested State not to comply in whole or in part with a request for assistance and the reason
for that decision.