My X5 won't start, WTF?

[dmvx5]

So my new-to-me CPO X5 4.8i arrived a couple of days ago. It seems the five days on the auto transport truck wasn’t good for the battery, and the truck wouldn’t start. There were no battery problems before I bought the truck last week (as confirmed by two PPIs at two independent BMW repair shops in the Los Angeles area). The transport driver gave her a quick jump start, and I was on my way.

I parked the truck over night, went to start her up on Saturday morning and the truck wouldn’t start.

I let it sit for another day, and tried to jump start it using a Schumacher battery charger. Again, the truck didn’t start. In fact, after I tried to start it, everything went blank. After I disconnected the charger, the electronics were on the fritz and then the power went out completely.
Then I happened the press the hazard lights button and that was on the fritz too.

I don’t know if I killed my battery, blew a fuse, or both. Does anyone have any idea what could be wrong with the truck?