Gabriel Du Pre Series by Peter Bowen

When a thirty-year-old plane wreck is discovered, French-Indian cattle-brand inspector Gabriel Du Pre takes up his deputy duties to find out why one of the skeletal remains has a bullet hole in its head.

In Toussaint, Montana, old family secrets, forgotten for more than 100 years, come to light after a young woman and her land-owning parents die under suspicious circumstances.When Larry Messmer, the brother and son of the victims, auctions off his parents' ranch, Gabriel Du Pre discovers a string of unexplained deaths buried deep in the family's past.