Widespread poverty, economic inequality and the spread of drug trafficking and gang violence have contributed to an increasingly savage environment in Honduras. Efforts by President Juan Orlando Hernández to fight mounting crime by creating a militarized police force have also contributed to an aggressive climate that further threatens women’s rights, according to a report by a coalition of Honduran women’s groups prepared for the United Nations.

“The climate of fear, in both the public and private spheres, and the lack of accountability for violations of human rights of women, is the norm rather than the exception,” said Rashida Manjoo, the United Nations special rapporteur on violence against women, after a July visit to Honduras.

Sofía Alvarado, 23, was a teacher and had been dating Mr. Ruiz for about three months, according to the girls’ mother, Teresa Muñoz. The sisters shared a bedroom in their mother’s modest home.

The director of the National Police, Gen. Ramón Sabillón, said at a news conference Wednesday that Mr. Ruiz had shot Sofía during an argument after she danced with another man at the party.

María José was shot twice in the back as she tried to flee, said General Sabillón, according to The Associated Press.

In a statement on the Miss World website on Wednesday, Julia Morley, the chairwoman of the pageant, said, “we are devastated by this terrible loss of two young women, who were so full of life.”

She said the pageant would hold a special memorial service with all of the Miss World contestants in London on Sunday. “We are receiving messages of condolences and support from our Miss World family across the world, who all share our sadness at such a tragedy,” she said.

The police in Honduras said a second man, Aris Maldonado, was also arrested on Tuesday.

On Wednesday, the owner of the water park, his wife and daughter were arrested on charges that they helped cover up the crime, officials said, adding that they expected to make additional arrests. Leandro Osorio, the director of the National Bureau of Criminal Investigation, told local news media that the police had found a gun in Mr. Ruiz’s possession that they suspect was used in the shooting. His white Toyota pickup truck had been used to move the women’s bodies and then sent to a nearby garage to be painted, Mr. Osorio said.