Skinwalkers by Tony Hillerman

The fraud in the story "Skinwalkers" was committed for the sole purpose of getting back at the American government. The reasoning behind the fraud was because a treaty that was signed at Fort Summer decades ago. This treaty promised things to the Indian people things, which were never delivered, such as one teacher for every thirty residents. Basically Dr. Yellowhorse was now making the government reimburse the hospital for the bills of people who had already been released and even for people who were already deceased. The reason this was done so easily was because there were no death certificates for the deceased and many people that were dead had no date of death along with there name. The cases where Dr. Yellowhorse easily covered up people that were still living because he worked in the hospital and had access to the financial data. This meant it was almost effortless for him to file faulty reports as often as possible.
The only problem that Yellowhorse ran into was that some people were starting to catch on. Onesalt had caught on to the hospital fraud and was building a case against Dr. Yellowhorse and the hospital. This is also the reasoning for why Endocheeney, Wilson Sam and Roosevelt Bistie had all been killed and furthermore why an attempt had been made on Jim Chee's life. Yellowhorse feared she would expose him so he had her murdered by making up a story that she just like the others was a skinwalker and they had put a curse on whomever did the particular killing (the mother). Before being shot Onesalt had spoken to officer Chee and Yellowhorse assumed that now he knew as well or would find out with time.
Chee probably should have caught wind of what was going on long before the end of the book. He was the detective on the case and I even realized what was going on before he did. The hardest part of putting two and two together was finding a motive, which throughout most of the book there didn't seem to be one. This was of course until