Njavro was the sixth witness for the prosecution in the trial of former Yugoslav People's Army (JNA) officers Mile Mrksic, Miroslav Radic and Veselin Sljivancanin, who are charged with the massacre of at least 264 wounded Croats and civilians at the Ovcara farm outside Vukovar, eastern Croatia, on 20 November 1991.
The witness said that the accused Sljivancanin and Radic led the JNA units that took over the hospital on 18 and 19 November 1991.
Njavro said that Sljivancanin brusquely dismissed appeals from a representative of the International Committee of the Red Cross to observe the agreement on the evacuation of the hospital, which had been signed by the JNA, the Croatian government and the ICRC.
The witness said that he had personally seen Sljivancanin and ICRC official Nicholas Borsinger engaged in a heated debate, with the JNA major behaving "arrogantly and victoriously".
Njavro further said that he had been arrested by Radic personally. He said that Radic first came to the hospital on 18 November and that he saw him there over the next two days.
"On the morning of 19 November he came with a soldier and said: I am Captain Radic. From now on you can consider yourself under arrest, and you must not leave this room," the witness said.
Njavro described how Serb paramilitaries, led by former hospital doorman Bogdan Kuzmic, would come to inspect the wounded and civilians in the hospital.
"Captain Radic and Kuzmic inspected the entire hospital. They went to all the rooms where the wounded and civilians were staying. Their aim was to identify some of the wounded and civilians who were to be taken out of the hospital and end up in Ovcara," Njavro said.
Njavro also spoke of the shelling of the hospital from 6 August until the fall of the town on 20 November when the wounded and civilians were taken from the hospital to the Ovcara farm and executed.