The reigning Miss Honduras, Maria José Alvarado, and her 23-year-old sister, Sofía Trinidad Alvarado, have been found dead, days after the two women disappeared in Santa Barbara, Honduras, according to the BBC. The women were murdered by Sofía Trinidad Alvarado’s boyfriend in a jealous fit of rage, authorities said.

The siblings vanished on Thursday, shortly before the 19-year-old beauty queen was set to leave for London to compete in the Miss World pageant. They had attended a birthday party for Sofía Trinidad’s boyfriend, Plutarco Ruiz, that night and were never heard from again.

Gen. Ramon Sabillon of the Honduras National Police said that the bodies were buried by a river bank near the spa where they were last seen, according to the Associated Press.

“We are 100 percent sure that it’s them,” said Leandro Osoria, the head of the National Bureau of Criminal Investigation, according to the BBC.

Sabillon said Ruiz confessed to shooting his girlfriend because she’d been dancing with another man. He then allegedly shot Maria José Alvarado as she tried to flee, the AP reported.

National Police agents escort Plutarco Antonio Ruiz, the boyfriend of Miss Honduras Maria Jose Alvarado’s sister, in Santa Barbara on November 18, 2014. (Str/AFP/Getty Images)

The Miss World contest begins Thursday in London. “We are devastated by this terrible loss of two young women, who were so full of life,” Miss World chairwoman Julia Morley said in a statement. Morley noted that the organization will hold “a special service” on Sunday to honor the Alvarado sisters “and say prayers for them and their family.”

Before the grim discovery Wednesday, Ruiz had been taken into custody by authorities because he was one of the last people to see the women alive. Another man, Aris Maldonado, the owner of the spa, was also detained this week. He is currently being held as an accomplice.

Police believe the two men attempted to bury the bodies near the river so that they would decompose quickly, according to the AP. Authorities confiscated weapons and a vehicle they believe were used to transport the bodies.

Police initially said they did not have evidence to suspect a kidnapping. Witnesses saw the two women leave the party in a champagne-colored car with no license plate, according to their mother, Teresa Muñoz.

Muñoz told the AP that Ruiz called her the next morning to tell her that the women had left the party in a car with people that they did not know.

They were reported missing on Sunday after they didn’t return home and did not respond to cellphone calls.

People demand the safe return of Miss Honduras Maria Jose Alvarado on Tuesday in Santa Barbara. (Str/AFP/Getty Images)

“They were not very astute about assessing the people around them. They were just friendly,” the sisters’ mother told Televicentro, according to the AP. “They were taken out by people they hadn’t known very long.”

Their bodies were found Wednesday morning in the Cablotales village near the Aguagua River, according to La Tribuna , which reported that the suspect and an accomplice were attempting to hide the bodies and clean the crime scene.

Salvador Nasrallah, who hosts the TV program “X O da Dinero” on which Alvarado had worked as a model, said the country’s systemic violence played a role in the crime.

“A lot of girls die this way, but because they’re not famous, it doesn’t get the attention and the crimes go unpunished,” said Nasrallah, a former presidential candidate. “She was a girl of good principles who fell into a trap, a game with guns, and ended up a victim of a violent system.”

The women went missing in a region that is heavily controlled by drug gangs, in a country wracked by violence. Honduras has the highest homicide rate in the world, according to the United Nations. In 2012, there were 90.4 homicides for every 100,000 people in the country.

In a travel warning to U.S. citizens,the State Department noted that some of the violence is due to gang efforts to control transnational drug-trafficking routes. Members of the Honduras National Police have also been known to participate in murders and car thefts. And many crimes are never prosecuted, if they are investigated at all.

[This post has been updated.]