A 27-year-old police officer on the country’s largest Indian reservation was fatally shot Sunday during a domestic-violence call, the Associated Press reported. Navajo Nation Officer Houston James Largo was airlifted to the University of New Mexico Hospital after receiving a critical injury during an incident in the town of Prewitt, New Mexico, but he died while there. FBI spokesman Frank A. Fisher said a suspect is in custody, but no further details were released. The FBI is investigating along with the Navajo Nation police on the reservation, which covers 27,425 square miles in Arizona, Utah, and New Mexico. New Mexico Gov. Susana Martinez offered her condolences to the tribe, saying the news of Largo’s death “reinforces the dangers our police officers face every day—so we and our families don’t have to.” “I’m confident the monster who took this brave officer from us will face the full measure of justice,” she said. Largo had served five years on the force.