By Cole Hill ( | First Posted: Mar 20, 2013 10:52 AM EDT

Arias was found guilty May 8 in the grisly premeditated first-degree murder of her ex-boyfriend, Travis Alexander, in June 2008. (Photo : MySpace: Jodi Arias)

As an "Expert Witness" for the defense claimed Jodi Arias suffered from Post Traumatic Stress Disorder and dissociative amnesia Tuesday, prosecutor Juan Martinez drew the psychologist's entire credibility into question.

A photographer from California, Arias is charged with the the grisly first-degree murder of her ex-boyfriend Travis Alexander in June 2008, when she allegedly stabbed the 30-year-old man 27 times, shot him in the face, slit his throat from ear to ear and left his bloodied corpse crumpled over in the bathroom shower of his home. Arias' fate depends on whether the jury believes she killed Alexander in self-defense, as she contends, or was actually a jilted lover exacting jealous revenge, as the prosecution argues.

Richard Samuels, the defense's first "expert witness," has testified that Arias suffered acute stress disorder following the harrowing incident. He said that disorder eventually evolved into PTSD. A psychologist and self-advertised "expert witness" on PTSD, Samuels said he met with Arias 12 times following her arrest and analyzed her murder case file, her journal entries, and news stories on the case to conclude that she had PTSD and amnesia. He also said he tested Arias for PTSD and acute memory loss with the Millon Clinical Multiaxial Inventory test and another unspecified test for PTSD. He testified that the print out showed Arias "responded in an accurate and honest manner during these tests."

Martinez noted that when Arias took her PTSD test she was still lying to everyone about her involvement in Alexander's death, maintaining that masked intruders had killed him. How was it possible, Martinez asked, for Samuels to accurately diagnose Arias when she herself later admitted to lying to him at the time.

"They can lie to about 10, 15, 20, 30, 50 things that you consider irrelevant ... and that still would not affect your opinion in this case, right?" Martinez asked, according to The Huffington Post.

"If there were 50, 60 points, yes, of course, it would raise an alarm to me," Samuels said.

Arias has already admitted to lying about Alexander's death to just about everyone. She first claimed she was never at Alexander's home the day he was killed. Then, when DNA evidence proved she was lying, she said masked intruders killed him, and finally, years later she backtracked to admit she killed the victim, but now claims it was in self-defense, saying he attacked her in the shower, forcing her to fight for her life. She claims she lied so often because she was "ashamed" she killed Alexander in self-defense and because she was afraid of revealing the details of their sexual relationship.

Samuels claimed Arias' numerous admitted lies weren't pertinent to forming a diagnosis. He said the PTSD test she filled out did all the work for him because it was a true reflection of how she felt at the time.

"The results of the [test] do not reflect whether someone is telling one story or another. What it does reflect is the internal state of the individual. She experienced the trauma even though she was telling a story that was different from what actually happened. So this test reflects her internal struggle, her internal emotional state and, in my opinion, is perfectly valid," Samuels testified.

"It's not critical to the outcome of the test," he added.

Martinez prodded Samuels to admit he could at best only speculate how his diagnosis of Arias would be effected by her lies.

"I'm speculating," Samuels agreed.

Sensing an opportunity to deflate his credibility, Martinez pounced.

"Right, made it up right now. Speculating," Martinez boomed.

"No, clinical judgment, sir," Samuels defended.

Martinez noted that Arias only meets two out of three criteria for PTSD in Samuels' report; PTSD diagnosis requires three.

Samuels claimed it was a simple typo.

"Isn't it true that - it's a counting kind of thing - three are required to be found in order for there to be PTSD, correct?" said Martinez.

"That's correct," Samuels said.

"You only listed two, right?" asked Martinez.

"That was a typographical issue," Samuels insisted.

"Is that yes or no?" asked Martinez.

"Yes, it is," responded Samuels.

"Sir, with regard to this, you're getting paid. How much are you getting paid per hour?" asked Martinez.

"I get paid per hour, $250," Samuels said.

"And for $250 an hour you're saying that you weren't paying enough attention to put whatever else was needed?" asked Martinez.

"I reviewed the report numerous times and I must admit I missed it," Samuels said.

With Arias finally off the stand, her defense is fighting an uphill battle to convince the jury she's finally telling the truth. The testimony of "expert witnesses" hired by the defense, such as Samuels, is expected to take over the next phase of the trial in an attempt to explain how her lies, odd behavior and "memory condition" are a result of PTSD, amnesia and domestic abuse.

Arias could face the death penalty if convicted. The defense will continue on redirect with Samuels Wednesday. The trial begins at 4 p.m. EST.

© 2015 Latinos Post. All rights reserved. Do not reproduce without permission.