A man suspected of the 2014 murder of Miss Honduras and her sister -- his girlfriend at the time -- declined to testify in a Tegucigalpa court on Friday on grounds of mental illness.
Plutarco Antonio Ruiz, 34, appeared to act oblivious to court proceedings once he was led in by police, court officials said.
He did not respond to questions directed to him in the Supreme Court, as the mother and a sister of the victims looked on.
Prosecutors accuse Ruiz of killing his 24-year-old girlfriend, Sofia Trinidad Alvarado, and her 19-year-old sister, Miss Honduras beauty queen Maria Jose Alvarado, on November 13, 2014.
The women's bodies were found buried on the banks of a river six days later -- on the date Maria Jose was meant to have flown to London to compete in a Miss World pageant.
Prosecutors believe Ruiz fatally shot the sisters in a jealous rage and then buried them with the help of accomplices.
The director of Honduras' forensic medicine institute, Julissa Villanueva, said that Ruiz "was completely competent" to stand trial and urged the judge to continue with proceedings.
The mother of the slain sisters, Teresa Rivera, said she believed Ruiz "wanted to get himself declared crazy so he can escape justice."
If convicted of murder, Ruiz faces up to 40 years behind bars for each of the victims.