The rocky highlands of Central Asia, in a remote region of Western Mongolia, are home to a plummeting population of the largest sheep in the world, the argali. The endangered species is beloved for its giant curving horns, which can run over 6 feet in length.

On a hunting trip this August, Donald Trump Jr. shot and killed one.

His adventure was supported by government resources from both the U.S. and Mongolia, which each sent security services to accompany the president’s eldest son and grandson on the multiday trip. It also thrust Trump Jr. directly into the controversial world of Mongolian trophy hunting — a polarizing practice in a country that views the big-horned rams as a national treasure. The right to kill an argali is controlled by an opaque permitting system that experts say is mostly based on money, connections and politics.

Trump Jr. received special treatment during his summer trip, according to records obtained by ProPublica as well as interviews with people involved in the hunt.