The first David Grann book I read was The Lost City of Z, which was an odd story but still very, very well written and good. I am currently on a true crime kick and I am looking to learn more about the history of the indigenous people in the US so this book was right up my alley.
This book details the conspiracy against the Osage Nation in Oklahoma, a group of people whose land was wealthy with oil deposits. He specifically focuses on a family that dies in ones in twos, by poisonings, gun shots and bombs and is a true story set in the early 1900's. These efforts weren't limited to this particular family however. Other members of the Osage nation were experiencing similar issues. Years pass without the murders being solved and the rest of America started to take notice. The Osage were well known on the national level - their oil had made them wealthy but the US government didn't think that they were capable of managing their own wealth so a law was passed requiring them to have guardians. They were also targeted by outlaws and theives who wanted to steal their land and wealth. The headrights were also extremely valuable and their existence is what led to the murders of the Osage, in the hope that they would then be passed on.
The FBI actually became involved in the case, helping to investigate and declare victory in the murders. In so declaring victory, the magnitude of the headright killings was obscured at worst, and minimized at best. Scholars think that the number that the FBI declared (24) was actually quite low. I loved this book and it is a necessary and intriguing read. You can find the book here (amazon link).