When court is done for the day, the conversation is only just beginning. Watch our new show, "HLN After Dark: The Jodi Arias Trial," nightly at 10 p.m. ET on HLN.

It was the eighteenth day of testimony from Jodi Arias Wednesday.  

Prosecutor Juan Martinez continued to challenge Arias on her version of how she killed her ex-boyfriend Travis Alexander.

The 32-year-old defendant claims she had to kill Alexander in self-defense in June of 2008 at his Mesa, Arizona home, even though she had given authorities other stories about the circumstances of his death. She faces the death penalty if convicted in her trial.

On Wednesday night, HLN’s Dr. Drew welcomed forensic crime scene expert Randolph Beasley to the show. Although Beasley has nothing to do with the Arias case, he knew both Alexander and Arias and gave his opinion on what he believed happened on that fateful day nearly five years ago.

“To me, what makes sense on this case is that Jodi did not bring a knife to attack Travis,” he said. “She brought a gun. It's obvious she premeditated this.  When she shot him in the bathroom when he's in the shower, the gun jammed, so she couldn't finish him off.”

He added, “When the gun jammed, she panicked. She had to go ahead and find a knife … and finished him off.”

Watch more of Beasley's theory in the video player above.

Dr. Drew On Call airs Monday through Thursday on HLN at 9 p.m. ET.  Follow the show on Facebook and Twitter @DrDrewHLN.

RELATED LINKS:

-Photos: Jodi Arias’ final attempt to sway the jury
-Jodi Arias trial: 142 evidence photos
-Arias prosecutor: 62 seconds to kill? 'Impossible'!