ALBUQUERQUE — Jerome Eskeets’s last sight before he fell asleep on a soiled mattress late on Friday, on an empty lot speckled by shards of liquor bottles and discarded syringes, was the stars that glistened up above — “a beautiful thing,” he recalled this week, drunk, already, at 9:30 a.m. A cousin lay next to him that night, their bodies warmed by the cheap vodka they had shared. It had been “a good night,” Mr. Eskeets said, until he felt a dull pain on the bridge of his nose, a punch by one of the masked assailants that surrounded them.

“Cowards,” Mr. Eskeets exclaimed on Tuesday as he stood by the scene of the crime.

The assailants kicked and beat them, Mr. Eskeets said, using their hands and whatever else they could find — a metal pipe, wooden sticks, cinder blocks. Mr. Eskeets eventually broke free and ran away. His cousin, whose name he said was Al Gorman, and another homeless man he knew only as Cowboy, ended up dead. The police said they had both been disfigured beyond recognition by the thrashing, which included having their heads smashed repeatedly with the cinder blocks.

Someone directed the officers to a stucco house on the other end of the lot, where a 15-year-old boy came to the door wearing shorts splattered in blood. Later, the boy told detectives that he, his 16-year-old half brother and their friend Alex Rios, 18, had taken turns assaulting the men. According to a criminal complaint, the teenagers had been “randomly attacking homeless people for over a year” and, by the 15-year-old’s estimates, they had beat up more than 50 since moving to the stucco house some months ago, as if it were a distraction, or a sport. As far as anyone could tell, though, this was the first time the beatings had resulted in deaths.

The killings exposed some of the profound social ills — alcoholism, abject poverty, neglect — that have long plagued New Mexico, a place best known for its stunning landscape. Since 1997, the state has led the nation in the number of alcohol-related deaths, according to the Centers for Disease Control and Prevention. There is a large homeless population and, in a strange twist, a man named Victor Prieto, who identified himself as the father of the two boys, told KOB-TV in Albuquerque that he and the boys had been homeless at one point. (No one came to the door on Tuesday or Wednesday at the apartment where the family lives.)