Police in Honduras said they have detained four suspects in connection with the disappearance of Maria José Alvarado, otherwise known as Miss Honduras 2014, and her sister, Sofia, who have been missing since Thursday.

Honduran authorities said they initially detained 10 people but later released six of them. The remaining four are being held for questioning, among them Plutarco Ruiz, the boyfriend of Alvarado’s sister, as well as the owner of the spa where the women were last seen.

Witnesses said they last saw Maria José, 19, and Sofia, 23, on Nov. 13 leaving the spa in Santa Barbara, Honduras, with three men. They were on their way to a party to celebrate Ruiz’s birthday. Their mother, Teresa Muñoz, told local reporters she repeatedly called their cellphones that evening with no answer and then reported them missing on Saturday.

Maria José had been crowned Miss Honduras 2014 in April and was scheduled to fly to London on Sunday ahead of the Miss World competition in December.

The disappearances could bring heightened global attention to crime in Honduras, which has the world’s highest murder rate, as the international beauty competition goes forward next month. Honduran police said they found no evidence of a kidnapping because the Alvarado family had not received any ransom demands.

Chief prosecutor Gabriela Carranza said authorities were following some leads in the case but could not reveal any further details of the ongoing investigation.