Nowhere in the article do they mention the caliber of the firearm . . . since they do mention a 10-round magazine, it could have been a Beretta 92 (9mm) or something even smaller, like a .380 auto or even a .22 rimfire. Some describe 9mm as ".45 ACP set on 'stun'" - or, as my dad says, "I hate like &*^*^% to shoot a man and then stand there and argue with him."
Suffice it to say that NONE of those are adequate for gator. If she had unloaded a .44 Mag or a .45 ACP into Mr. Suitcase, she might have gotten his attention a little more effectively.
See my post 51. We don't know, but it was probably just a virtue pistol -- although if she's a Marine you'd think she'd have something a little more substantial around the house . . .