Golfito, Costa Rica ? Lawyers made final arguments Wednesday in the trial of three Costa Ricans accused of killing Kansas University student Shannon Martin.

A three-judge panel hearing the case refused to allow testimony by a final, unidentified prosecution witness because that testimony was based on hearsay. But they permitted a video of Martin’s autopsy to be shown in court.

Only the defense, prosecution and the judges were allowed in the courtroom during the presentation of the video. Martin’s mother, Jeanette Stauffer, said she did not want others to see her daughter’s condition following the autopsy.

Rafael Zumbado Quesada, 52; Kattia Cruz, 29, and Luis Alberto Castro Carrillo, 33, are charged with homicide in Martin’s death. The case is not being heard by a jury and will be decided by the three-judge panel.

Prosecutors also expressed regret that they have not been able to find another potential witness, a taxi driver who allegedly picked up the suspects after the killing. A gas station employee said he saw blood in the taxi after the suspects got out.

The judges scheduled a final court session for summations and closing arguments for Monday.

Martin, a 23-year-old student from Topeka, Kan., was stabbed to death May 13, 2001, after she left a nightclub in Golfito, about 100 miles south of the Costa Rican capital, San Jose. Martin was in the country to gather specimens for a biology project.

Stabbed 15 times, Martin’s body was found along an airport access road about 100 feet from the home of the Costa Rican family she was living with.

On Friday, a key witness in the case, Rosibel Munoz, was forced to give her testimony behind closed doors because of death threats. Shortly before Munoz was scheduled to testify, the courthouse office of the prosecutor received a call saying, “If Rosibel testifies, we’ll kill her.”

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Stauffer, who had offered up to $50,000 to anyone who could provide information about the killing, has traveled to Costa Rica constantly since her daughter’s death and vowed to remain in Golfito for the duration of the trial.

On Tuesday, Stauffer — who traveled to Costa Rica for the trial — reportedly received death threats at the hotel where she was staying along with other family members, said Raul Quesada Galagarza, head of law enforcement authorities for all of southern Costa Rica.

Extra police were assigned to guard the court following the threats, and Stauffer also was protected by private security guards.

Quesada Galagarza said a caller threatened to kill Stauffer but would not say if the threat was heard by Stauffer directly or by someone else.