ROME — The war crimes trial of former SS Capt. Erich Priebke took a dramatic turn when a key prosecution witness, another former Nazi in his 80s, injured himself in an attempt to escape testifying.

Former SS Maj. Karl Hass, 84, broke his pelvis and damaged his backbone before dawn Friday of last week as he fell 15 feet from a second-floor balcony while trying to escape from his Rome hotel.

Police had been guarding the door of his hotel room.

Hass, who used a jacket to help lower himself to the ground, was due to testify for the prosecution in the Priebke trial later that morning.

Priebke, 82, is on trial before a Rome military court for his involvement in the March 24, 1944 Nazi mass execution of 335 civilians at the Ardeatine Caves, south of Rome. About 75 of the victims were Jewish.

The Nazis ordered the massacre in response to an Italian partisan attack the day before in which 33 German soldiers were killed.

Hass' attempted escape came after he met with prosecutor Antonio Intelisano for a lengthy preliminary interrogation.

Hass came to Italy voluntarily as a witness, but he also is being investigated as a suspect in the massacre, court officials said.

Hass has denied any part in the Ardeatine Caves massacre.

Hass, who will remain in a military hospital for about a month, will testify this week from his hospital bed, officials said.

"I found Hass to be in good shape, apart from the injuries. He said his decision to try to flee was provoked by heavy stress," Intelisano reportedly said.

Intelisano added that "had Hass not wanted to testify, he could have gone straight home through the front door.

"There are no restrictions on his freedom," the prosecutor said.

Hass was involved with espionage and secret service operations during the war. He was on the staff of the German Embassy in Rome.

Hass was presumed dead for years, until depositions by Priebke indicated that he was living in Italy. Investigators found him in a small town near Milan, but he fled to his daughter's home in Switzerland.

Intelisano convinced him to come to Rome to testify.

Hass has accused Priebke of involvement in the massacre. He also linked him to the killing of an Italian union leader before Allied troops entered Rome in 1944.

Priebke's lawyer Velio Di Rezze has implied Hass was protected by the Italian secret service afterward.

"He tried to escape because he realized that he was digging his own grave," Di Rezze said.