ABILENE, Texas -

Accused mother Tiffany Klapheke was “always a half a step away from a train wreck” even when she was “functioning at her best,” a neuropsychologist testified Monday.

When she was at her worst, Samuel Brinkman said, she was untrustworthy, dishonest, self-victimizing and hyper sexual.

Klapheke, 23, is on trial for allegedly failing to provide adequate food, water and medical attention to her and Thomas's 22-month-old daughter Tamryn before the toddler died on Aug. 28, 2012. The child’s two young siblings were also found in deteriorating conditions but ultimately survived.

According to Brinkman, who spent more than 19 hours evaluating Klapheke, she has a disorder that causes her personality to break down and for her to lose memory.

Brinkman said dissociative episodes are Klapheke's reaction to stress and that she experienced them around the time of toddler Tamryn's death.

Brinkman’s testimony came as the trial entered its third week Monday.

Meanwhile, the jury spent time Monday listening to Klapheke's 911 call that she made after realizing Tamryn was unresponsive.

Jurors will finish 911 tape Tuesday.

So far jurors have heard Klapheke screaming and crying hysterically, impossible to understand her words.

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Last Friday, when Thomas Klapheke appeared in court, was the first time he had seen ex-wife Tiffany since she dropped him off for a July 2012 deployment and said she wanted a divorce.

Tiffany Klapheke, 23, is on trial for allegedly failing to provide adequate food, water and medical attention to her and Thomas's 22-month-old daughter Tamryn before the toddler died on Aug. 28, 2012. The child’s two young siblings were also found in deteriorating conditions but ultimately survived.

The prosecution finished cross examining Thomas Klapheke on Monday morning. He said he had volunteered to deploy to Oman in July 2012 in order to make more money and replace another airman who had a family emergency.

TIffany Gann, a former Child Protective Services worker who resigned following a brief affair with Thomas that began in September 2012, also testified Monday. During a Friday hearing, District Judge Lee Hamilton decided the affair would not be brought to the jury's attention. 

Gann wasn’t the on-call CPS investigator the day of Tamryn's death; however, the investigator who was on call, Rebecca Tapia, had asked her to assist in the death investigation because Gann had been involved in two death investigations prior to Tamryn's death. Gann took photos of the home, accompanied the surviving Klapheke children to the hospital, sat in on a Aug. 29, 2012 CPS briefing and attended a 14-day hearing that determined what would happen to the surviving children.

She said she wasn’t involved in the Klapheke home prior to Tamryn's death but, as a result of the death investigation, did review the three CPS investigations that had been previously opened on the home. The third investigation was improperly closed six days before Tamryn died.

Gann said the purpose of the briefing was to determine who would take over the death investigation. She said more CPS supervisors than usual attended that meeting. The supervisors included Bit Whitaker and Gretchen Denny, who are currently persons of interest in a criminal investigation related to the Klapheke case. Abilene police began investigating CPS supervisors following Tamryn's death because they were suspicious of tampering with evidence. A special prosecutor is handling that investigation and no formal charges have yet been announced. 

During cross-examination, prosecutors asked Gann if she thought several supervisors were present because the case was one of the worst she had ever seen. Gann agreed but on re-direct, defense attorneys asked if she thought the supervisors were there because of CPS mistakes in the case. Gann said she didn’t know.

Gann said she had two conversations with Thomas about the case. She said during one conversation, they talked about the unsanitary conditions of the home and the conditions the kids were found in. During the other conversation, she had only asked how the surviving children were doing. She said they never talked about Tiffany Klapheke.

Prosecutors asked Gann if she thought some scratch marks on Tamryn's crib were teeth marks from bites. She said it was likely; however, defense attorneys pointed out Gann had only photographed one side of the crib's railing and so it was difficult to label the scratches as bites because there weren’t  two sets of marks that would match teeth marks from each of the child's jaws.

The trial entered its 11th day and third week Monday in District Judge Lee Hamilton’s court.