Friends and family members stand around the coffin of Maria Jose Alvarado at the cemetery in Santa Barbara November 20, 2014. [Photo/Agencies]

Lt. Col. Ramon Castillo, a top law enforcement officer in Santa Barbara, said eight more people were at the gathering at the spa that night and more arrest warrants were expected.

"The two original detainees had help from other people," Castillo said.

The mayor of Santa Barbara arranged for two plastic tents to shelter mourners from the rain outside the Alvarados' home, nestled along an unpaved road in western Honduras. TV cameras crowded around the house.

"This is going to put an end to the normal life of the town. It means the end of freedom for young women," said Mayor Juan Alvarado, who is not related to the family. "Parents are not going to let them leave home on their own anymore. The image of Santa Barbara and of Honduras has been stained forever by this horrible crime."

The killings highlight what experts call an alarming trend of increased violence against women in Central America, fueled by crime, poverty, male chauvinism and domestic abuse. According to the United Nations, slayings of women and girls in Honduras increased 263 percent between 2005 and 2013.

The country has the world's highest homicide rate for a nation not at war, with an estimated 90 to 95 killings per 100,000 people. Street gangs and drug traffickers are the de-facto authorities in many areas, enforcing their will through violence, fear and extortion.

"If nobody here reacts against organized crime, it's because they control everything," the mayor said. "Because everyone fears them, and the military and police don't do anything. Everyone knows who they are."