Pretoria, South Africa (CNN) -- The prosecution in the Oscar Pistorius murder case expects to rest early next week, prosecutor Gerrie Nel announced unexpectedly on Wednesday.
Nel has only four or five more witnesses to call, he declared to the shock of the courtroom just before lunch on the 13th day of the trial.
He requested and got an adjournment until Monday to consider the state's position in the case.
The surprise move prompted questions about whether Nel was thinking about throwing in the towel, whether he had surprise new evidence to study, or whether the state's case was simply running ahead of schedule.
Pistorius, 27, could take the stand in his defense as early as next week if the case goes ahead as planned.
His legal team has the option of moving for the whole case to be thrown out -- or "discharged," in South African legal terminology -- once the prosecution rests.
But it's not clear that the defense has so completely rebutted the state's case that the judge would end it there.
Eighteen witnesses have testified for the prosecution in the 13 days since the trial began, including three on Wednesday.
The most dramatic testimony of the day came from police Capt. Christian Mangena, who testified that Pistorius' first shot hit Steenkamp in the hip, knocking her back onto a magazine rack, and that two other shots then hit her arm and head.
Pistorius admits firing the shots that killed his girlfriend but has pleaded not guilty to murder, saying he thought she was a burglar and he believed he was acting in self-defense.
He fired four shots through the door to the toilet room in his house in the middle of the night, probably killing her almost instantly with the shot to the head, according to the autopsy.
Blood in the bathroom
Mangena testified that Steenkamp was behind the door and facing it when the first shot hit her, then seated in a defensive position with her hands over her head when the other two bullets ripped into her body.
She then fell forward toward the toilet, the ballistics expert said.
Police blood-spatter expert Ian van der Nest testified later on Wednesday that blood in the toilet probably came from Steenkamp's head wound, while blood on the floor in front of it probably came from the wound to her right arm.
In court, Pistorius stuffed his fingers in his ears and leaned forward with his hands over his face each time Steenkamp's fatal injuries were discussed.
His defense lawyer Barry Roux disputed Mangena's theory about the position of Steenkamp's body and the order in which the shots hit her, saying experts would prove the police officer wrong.
The verdict may hinge on whether there was time for Steenkamp to scream between shots, giving Pistorius a chance to realize his mistake and stop shooting.
Roux argues that Pistorius fired four shots in quick succession, or two "double taps."
Mangena said that was "impossible," since there would have been no time for Steenkamp's body to change positions between shots.
Prosecutor Nel pointed out that the first witness, neighbor Michelle Burger, said she heard a pause after the first shot, then three more in quick succession.
"That is possible," Mangena said.
Not on his prosthetics
He described Tuesday how he used lasers to track the path of the bullets that Pistorius fired through a door, coming to the conclusion that "the shooter was most likely not wearing prosthetic legs."
After initially disagreeing over whether Pistorius, a double amputee, was wearing his prosthetics when he killed Steenkamp, the prosecution and defense now agree that he was not.
That he was not wearing his prosthetics is a vital part of his defense. He argues he was justified in shooting through a toilet room door because he is particularly vulnerable when he is on the stumps of his legs.
Blood spatter expert van der Nest took the stand after Mangena.
He testified that the pattern of blood he saw in the house was not only "consistent" with Pistorius' version of events, but was the "most probable explanation."
Pistorius says he carried Steenkamp's body downstairs from the toilet room to the entranceway of his house after he shot her.
Photos of blood spatter on the stairs have been shown to the court several times.
Van der Nest also testified that there was no evidence of "blunt force trauma" to Steenkamp's body, suggesting there is no evidence Pistorius hit Steenkamp.
After van der Nest, police cell phone data expert Michael Sales testified briefly. He said he downloaded data from two iPads found in the house, but didn't reveal what was on them.
Neither side asked him.
The browsing history of one was cleared several hours before Steenkamp was killed, and it was not used after 9:19 p.m. that night, he said. That's consistent with Pistorius' story that the couple went to bed around 10.
About five hours later, Pistorius shot Steenkamp through the door, hitting her with three hollow-tipped bullets, one of which probably killed her almost instantly.
Pistorius says he heard a noise in the middle of the night after getting out of bed, did not realize that Steenkamp had also gotten out of bed, got his gun and shot her in a case of mistaken identity.
Pistorius first achieved fame as an outstanding double amputee sprinter who runs with special prostheses that earned him the nickname "Blade Runner."
The case against Pistorius is largely circumstantial, Nel said in his opening statement on March 3. Pistorius and Steenkamp were the only people in his house when he killed her.
Nel has been building a picture of what happened through the testimony of police officers, experts, neighbors who heard screaming and bangs that night, current and former friends of Pistorius' and a security guard who sped to the scene because of reports of gunshots.
Neighbors said they heard a woman screaming before the shots were fired. But the defense is proposing that what neighbors thought was Steenkamp screaming in fear for her life was in fact Pistorius when he realized what he had done.
And the defense says that the sounds neighbors heard were not the gunshots, but a cricket bat hitting the door as he tried to rescue her.
Judge Thokozile Masipa will decide the verdict with the help of two lay people called assessors. South Africa does not have jury trials.
In South Africa, premeditated murder carries a mandatory life sentence with a minimum of 25 years. Pistorius also could get five years for each of two unrelated gun indictments and 15 years for a firearms charge he also faces.
If he isn't convicted of premeditated murder, the sprinter could face a lesser charge of culpable homicide, a crime based on negligence.
The sentence for culpable homicide is at the judge's discretion.
The trial is currently scheduled to run through April 4, take a break, and resume in mid-April.
CNN's Robyn Curnow, Brent Swails, Nicola Goulding and Emily Smith contributed to this report.