The bodies of María José Alvarado Muñoz, the reigning Miss World Honduras, and her sister, Sofia Trinidad Alvarado, were found in a mountainous area beside a river after they had been missing for several days, Honduran police said in comments aired by CNN affiliate Televicentro.
Plutarco Antonio Ruiz Rodriguez and Aris Valentin Maldonado Mejia are now in police custody, and investigators believe more people are involved in the sisters' deaths, Police Commissioner Rolando Casco Torres told Televicentro.
Ruiz is Sofia's boyfriend, police say, according to CNN en Español.
The sisters disappeared last Thursday night after going to a spa for a birthday party for Ruiz in Santa Barbara, northwest of the capital of Tegucigalpa, police told CNN en Español.
Ruiz is suspected of killing the two sisters, said Leandro Osorio, chief of the National Bureau of Criminal Investigation.
Ruiz also "is considered the person who was most in contact" with the victims, Deputy Police Commissioner Rolando Casco added, according to Televicentro.
Alvarado, 19, was supposed to leave for London soon to participate in the Miss World pageant, police said.
Their family reported the women's disappearance on Saturday. Their mother, Teresa Muñoz, initially believed her two daughters were kidnapped.
Eduardo Zablah, director of the pageant in Honduras, told Televicentro
that Alvarado and her sister were last seen getting into a vehicle after attending a party last week.
The young woman was to be among the contestants from more than 120 countries who arrive in London this week
for early rounds of the Miss World pageant. The final round is scheduled for December 14.
A student from Santa Bárbara, Honduras, Alvarado beat 18 contestants to win the Miss World Honduras crown
In her profile on the pageant's website
, she described herself as "dedicated" and said she would someday like to go into government, specifically as a diplomat for her country.
She also said that she liked playing volleyball and soccer, eating Honduran food and performing the country's traditional punta dance.
Julia Morley, the chairman of the Miss World pageant, said contestants will hold a special service Sunday to honor Alvarado and her sister and offer prayers for their families.
"We are devastated by this terrible loss of two young women, who were so full of life," Morley said.
Honduras has the world's highest murder rate
, the United Nations reported earlier this year, with 90.4 homicides per 100,000 people in 2012.