The day you going to send her is the day your helper knows about it, she won't have chance to steal more things or do anything else. Have some family members with you when you do that. I dun think agency will send runner. You can let the agency know that u are sending the helper back to them. Can seek their advice. I send my helper to the agency once when she stole things.
Best to consult with an agency so they can assist with the entire process.
My previous helper also stole my baby’s hand sanitizer!!