Relatives of those killed sobbed and embraced during the autopsy presentations. Pictures of the victims' injuries were not shown in court but distributed to the judges, prosecutors and defense lawyers as well as the psychiatrists who are examining Breivik during the trial.
Breivik claims the attacks were "necessary" and that the victims had betrayed Norway by embracing immigration.
As he has for most of the trial, now in its seventh day, the far-right fanatic remained mostly expressionless during the hearing Tuesday. But he smiled when a security guard, who was inside the government high-rise when the bomb exploded, called Breivik's motive for the attacks "totally absurd."
Describing the confusion that followed the blast, police operations leader Thor Langli said the initial reports he received suggested there were two suspects, and two other bombs about to explode.
Langli recalled standing next to the head of an anti-terror squad in Oslo when he received a call about the second attack at the Labor Party's youth camp on Utoya, some 40 kilometers (25 miles) from the Norwegian capital.
"I saw on his face that it was something serious," Langli said. "And while I was watching him he said out of the corner of his mouth, 'Shooting on Utoya.'"
Another report came in that about 50 people had been shot on the island. The anti-terror unit was dispatched to Utoya. When it arrived, some 70 minutes after the first reports of Breivik's rampage, 100 people had been shot.
The self-described militant nationalist testified last week that he had expected to be shot by police after the bombing. But no one stopped him as he walked to a getaway car parked near the bomb site, and drove to Utoya.
"I estimated the chances of survival as less than 5 percent," Breivik said last Thursday.
Langli said he first got a report of a suspect with a "non-Nordic" appearance leaving the scene of the bombing. He then got another report of a Nordic-looking suspect, which made him believe there were two suspects.
When he heard about the Utoya shooting, he started thinking the bomb and the massacre were the actions of the same person.
"I thought there was a connection. But I didn't have any evidence for that," Langli said. Turning to Breivik, he added: "I could not imagine there being two people with so many crazy ideas."
Two examinations conducted before the trial reached opposite conclusions on whether Breivik is psychotic, the key issue to be resolved during the trial.
A security guard who was in basement of the Norwegian government high-rise struck by the car bomb testified Tuesday that he and a colleague used security cameras to get a closer look at the white van that Breivik had parked in front of building.
"The moment we had zoomed in on the plate the car exploded," said Tor Inge Kristoffersen, who was not hurt in the bombing. He described the scene in downtown Oslo as a "war zone."
Svein Olav Christensen, an explosives expert working for a defense agency, showed pictures of the bomb site to the court. The 2,000-pound fertilizer and diesel bomb had ripped holes in the concrete platform underneath the vehicle, and also in the subterranean floor below.
Breivik has said he was disappointed when he found out that the 17-storey building had not collapsed. Christensen said the bomb would have had to be "much larger" to bring down the structure.
The trial is scheduled to go on for nine more weeks.