The scandal mounting over Three Cups of Tea author Greg Mortenson's Montana-based charity has quickly moved from a media embarrassment to a possible criminal matter. Montana Attorney General Steve Bullock has started looking into charges that Mortenson's Central Asia Institute spent an inordinate amount of its donation money to enrich Mortenson instead of its stated mission of building and operating schools in Pakistan.

The investigation comes just a few days after a 60 Minutes report questioning the accuracy of Three Cups of Tea, Mortenson's best-selling account of living with villagers in Pakistan after he got separated from his K2 climbing party in 1993, which inspired him to start the CAI. That report was based on mountaineer John Krakauer's recently released report, Three Cups of Deceipt, which attacks Mortenson's work as fraud.

For Bullock, the question is not about the accuracy of Mortenson's book, but whether he misused donations to his charity. Here's the Associated Press's summary of the financial discrepancy:

Tax information filed with the Internal Revenue Service for the fiscal year ending Sept. 30, 2009, the most recent available, put the charity's expenses at $9.7 million. Of that, $3.9 million — about 41 percent — was spent on building materials, teacher salaries, scholarships and other expenses related to school building.

A larger amount, $4.6 million, was spent on what was described in the tax documents as "domestic outreach and education" and "lectures and guest appearances across the United States." Mortenson, who is the Central Asia Institute's executive director and a board member, received $180,747 in compensation that year.

More than $1.5 million of the charity's expenses went to advertising and marketing Mortenson's books.

Mortenson has said much of the money went to educating people in the United States about the need for schools in Pakistan. The AP pulls a quote from his recent Outdoor magazine interview: "Our education mission includes both educating young people in Pakistan and Afghanistan--especially girls--and educating the American public about how promoting education in these countries contributes to peace."

Justifying those costs against a potential criminal fraud investigation will now be the job of Mortenson's lawyers.