<human>: Give me the gist of the text in a nutshell

Okay so I could use some advice - I live in a house with 4 other people at university. Two of us have been diagnosed with ADHD, and we are both prescribed different medications as treatment. One of our other roommates has been stealing our pills. Her boyfriend is also involved. We have hidden them in multiple places, and counted them very carefully each time to ensure we were not going crazy. We confronted her earlier on in the semester the first time it happened, and she completely denied it. Absolutely all of the facts point to her and her boyfriend taking them. I would be happy to explain this further in the comments if need be. 

At this point I am looking for advice on how to handle the situation going forward. I considered this girl to be one of my very best friends, but now it doesn't seem that way. 

1. How can my roommate and I prevent the stealing from  continuing? Medication is very expensive, and we require it every day. 
2. How can we get proof that it is our one specific roommate and her boyfriend that are the ones stealing it? Each time we confront her it is complete denial and I am over her playing that game. 
3. Are there any additional steps I can take to improve the situation? 

Thank you!
<bot>: Roommate is stealing Adderall from myself and another roommate. Need advice on how to handle it and how to get proof it is her.