Colony Down — David Robbins

The United Nations Interplanetary Corps was created to protect the colonists on Mars. For over a century there was nothing to protect them from. Then indigenous life was discovered. Creatures that didn't like having their planet invaded. Captain Archard Rahn has already lost one colony. He refuses to lose another. But to prevail, he must unravel secrets within secrets. Why have his superiors been lying to him? And why do the Martians always take the heads of those they slay? COLONY DOWN is a riveting novel that takes the reader on a roller coaster ride of thrills and chills.