Rocky Road Brownies and a Cookie Thief

My favorite thing to do in the kitchen is bake cookies or brownies. I have some friends at work that I pack little baggies of treats to share with. I usually send a few to a neighboring branch and the last couple treats have not made it to their intended recipients. There is a cookie thief in my company! My poor friends are calling wondering where their weekly caloric sugar rush is....What is a baker of treats to share to do?!? So, to replace the oatmeal cookies I sent out yesterday (that disappeared) I am hand delivering some rocky road brownies tomorrow morning. Any ideas on cookie thievery revenge? Don't get me wrong, I'm totally willing to share with whoever it is that is so desperate for homemade baked goods they will take someone else's treats, but culinary justice must be served. LOL