This Week in Jodi Arias Trial: Killer Wraps Up 18th Day on Stand, Defense Doc Claims PTSD Caused Arias' Memory "Fog"

Jodi Arias self-portrait

"I'll agree with that," Arias said.

The jury will have to decide if Arias is lying -- or the picture is lying.

They will choose the picture.

Once the jury members decide Arias must be lying about getting the gun from Alexander's closet, they'll be forced to agree that the most likely alternate explanation is that she brought the .25-caliber pistol from her grandparents' home, as police and Martinez have theorized.

Our feature article this week covers one aspect of the gun that Martinez hasn't picked up on yet. As we wrote, the .25-caliber pistol is relatively rare these days. They were popular in Arias' grandparents' earlier years, but not so much now.

In researching our feature article, we called several gun shops. They confirmed what we already knew: That the odds are absurdly high that the admitted killer's grandparents .25-cal went missing, and Alexander happened to have a .25-cal in his closet.

Alexander was a successful, young, law-abiding businessman who could have any firearm he wanted. One gun shop manager confessed that if a customer such as Alexander had walked in, asking about purchasing a gun for home protection, salesman would never have suggested a low-powered .25-caliber, and would have steered him away from such a purchase if Alexander had expressed a desire to own one. The .25-caliber makes a good pocket gun, being easy to conceal, but has minimal stopping power.

Another gun store said it did not normally carry .25-caliber target rounds, because of the low demand, but did have some .25-caliber hollow-point defense rounds for sale.

Martinez ought to put a firearms expert on the stand to talk about this issue. Not that he didn't do a good job grilling her over why she thought Alexander would be intimidated by a gun that he'd told her he always kept unloaded.

But whether he does or not, the jury will have a hard time swallowing the coincidence of the "two" .25-caliber handguns -- the grandparents' and the one Arias says Alexander had.

If Arias brought the gun from California, then the crime was premeditated. And that's why we can't shake the idea that Arias is, indeed, headed for death row.

In other Arias news:

*A couple of new videos surfaced this week: One shows Alexander telling his friends how he was once robbed at gunpoint.

Alexander explains how he had a "gun at my temple," and -- eerily -- had images in his head of lying in a pool of blood.

Another interesting vid shows Arias laughing to herself and doing a headstand in a police interrogation room.