The president of the Navajo Nation condemned the beating deaths of two Native American homeless men in New Mexico as a hate crime, and called on Thursday for a federal investigation into slayings that police have blamed on three teenagers. Prosecutors have charged three Hispanic teens, ages 15, 16 and 18, with murder in the fatal beatings of the homeless men on July 18 in Albuquerque in violence so brutal it left the men’s bodies badly disfigured.