Oscar Pistorius Murder Trial: Social Worker Doubts Olympian's Court Outbursts Are an Act

May 8, 2014 — -- Oscar Pistorius' former probation officer, who saw him a day after the killing, does not believe the double amputee Olympian is putting on an act by sobbing, vomiting and openly displaying his emotions during his trial for the murder of his girlfriend, she told the court today.

Yvette Van Schalkwyk, a social worker first appointed to provide emotional support for Pistorius and later to write detailed reports about his state of mind, said she approached the defense earlier this week and asked to testify. She said she was upset and unsettled by suggestions that the man dubbed the Blade Runner was putting up an act in court to avoid answering questions and even took acting lessons to hone his performance in court.

Van Schalkwyk testified about the emotional wreck she encountered when she first met Pistorius during his bail application.

"I saw a heartbroken man that's suffering emotionally," she told the court. "He said to me he accidentally shot her.

"He vomited, twice," she added. "And one time, when he came out of court, he just sat down and started crying and crying."

Gerrie Nel, the chief prosecutor, objected to van Schalkwyk's testimony, but the court judge allowed it. Nel suggested Pistorius' behavior after the killing was caused by him feeling sorry for himself.

"It's all about him," the prosecutor said.

Over the past two months, Pistorius has been see in in court doubling over and crying, weeping and retching into a bucket.

Pistorius is charged with killing his girlfriend, Reeva Steenkamp, in a pre-dawn shooting at his home on Valentine's Day 2013. The state has claimed he knew Steenkamp was cowering behind a locked bathroom door when he fired four shots through it, but Pistorius has said he mistook her for an intruder and thought he was acting in self-defense.

Today, Van Schalkwyk and two other witnesses were called to testify in the high profile trial in Pretoria, South Africa -- including the defense's ballistics expert, Tom "Wollie" Wolmarans.

Judge Thokozile Masipa has made it clear that she will not tolerate any further delays -- and Defense Advocate Barry Roux's three witnesses called today brought the total number of defense witnesses to date to 11.

At the start of the defense's case, Roux indicated he planned to call between 11 and 14 witnesses. He added this week in court that he expected to wrap up early next week.

Anesthetist Christina Lundgren was called first today in an attempt to disprove the state pathologist's evidence.

During the state's case, the pathologist testified that he found partly digested vegetable matter and a white, cheese-like substance in Steenkamp's stomach, which, in his opinion, meant she had eaten no more than about two hours before her death.

At issue was whether or not Steenkamp was awake and could have eaten or whether she was sleeping, as Pistorius claimed. Prosecution testimony suggested a person's stomach is normally empty after six hours, but Pistorius had said he and Steenkamp ate at least eight hours before the shooting.

The state argued she was awake before the shooting and the couple was arguing -- an argument that ended in Pistorius firing at the door, resulting in Steenkamp's death.

However, Lundgren said gastric emptying as a means to determine time of death is a notoriously inaccurate and inexact science. She told the court several factors could influence the rate of digestion, including the facts that Steenkamp was premenopausal, exercised before she went to bed and was asleep -- but she would not go as far as to say the pathologist was wrong.

Roux saved what was arguably the most significant witness after Pistorius himself, Tom "Wollie" Wolmarans, for the afternoon session.

Wolmarans, an extremely experienced forensics and ballistics expert, gave the court a detailed account of how a firearm works, how the South African Police Service's reassembly of the broken bathroom door and repeated probes through the bullet holes could have possibly caused variations in the test results, and said it would not be possible to accurately determine the sequence of shots.

He added that it was likely that Steenkamp was leaning slightly forward when she was wounded in the hip.

Wolmarans will continue his testimony Friday.

ABC News' Matt Gutman and The Associated Press contributed to this report.