RCMP have solved a bizarre mystery: How did $15.3 million in gold vanish from the Royal Canadian Mint? And while their report is still two weeks away, CTV News has learned the answer.

"Senior government officials say there was a colossal error at the mint itself," said CTV Ottawa Bureau Chief Robert Fife on Tuesday night.

Mint officials double-counted some gold bullion they sold, and also underestimated the shrinkage of the gold during processing.

The federal government had withheld bonuses for mint executives until the mystery was solved. It's unclear whether those bonuses will still be paid out.

Junior Transport Minister Rob Merrifield, who's responsible for the mint, called in the RCMP on June 9 after he learned that an audit would not "rectify the problem" of the missing gold. That's about 10 weeks after the government first learned of the missing gold.

The Deloitte and Touche audit cost taxpayers $360,000.

Ottawa now requires the mint to report on inventory levels of metals every three months.

Last month, Liberal critic for Crown corporations Joe Volpe said the security, reputation and the quality of the Canadian Mint's product has been compromised.

In early June, it was discovered that there was an unreconciled difference between the value of gold on the mint's books and the physical count of gold for the 2008 fiscal year.