Sister Caught Stealing from walmart?

My little sister (20) got caught stealing something worth $19.99, she'd stuffed it in her purse (like an idiot) and went on to pay for the groceries she did buy. She says it was some dumb manicure thing, she'd wanted but just couldn't afford after needing to pay groceries. Anyways, the LP stopped her at the front door, before she stepped out, and pulled her into the office thing for loss prevention. The man that stopped her called in a woman to stand by while he did whatever. He then asked for the item, she gave it back and offered her purse so he could check for more. He said no he'd known she'd only taken the one item. He took her ID, and asked her social security, he gave her a background check i'm guessing. The store manager came in, gave a receipt for the price of the item, and asked if he was going to call anyone (i'm guessing police?) The LP person said NO, and continued to write up some paper, after a bit he gave her ID back, and the manager person said she wasn't allowed on ANY walmart, Sams, etc properties or would be arrested. My sister apologized profusely for the embarrassing incident, and left as they told her to do. She knows what she did was wrong, she knows it was stupid, and has been insanely upset. She deserves the horrible feeling she's going through, but as her older sister and the person she lives with, i'd like to know what happens next? She said no one said anything about receiving a letter as a lot of the stuff we've looked up say will happen. Do you know anything that we should be looking forward to getting or having to do? Thank you for your time.