<human>: So the other day I noticed that my toothbrush was wet in the morning when I hadn't used it (I had last brushed my teeth the night before at 8pm). I compared it to my boyfriend's toothbrush and his was obviously dry. 

My bathroom is in the hallway and my other roommates have a bathroom attached to their room. A lot of the time they'll use my bathroom in the hall when one of them is sleeping and they don't want to wake them up. Now, this roommate in particular has friends and family that occasionally sleep over. At first I thought it may have been them, but she was the only one awake that morning when my toothbrush was wet and slanted over in the holder. It had obviously been touched.

I just heard someone tonight brushing their teeth and I'm pretty sure it was her new boyfriend that's sleeping over who doesn't have a toothbrush. I don't have any evidence of this other than my toothbrush was really wet. I brushed my teeth several hours ago and it must have dried by now. If my wet hair dried in that time, my toothbrush must have.

Also, an extra tube of toothpaste has been in there the past few days, but no toothbrush. 

How do I ask my roommate if her or her boyfriend are using it without sounding accusatory? Do I need more evidence? I'm not 100% sure. If I hide it in my drawer, they'll probably find it again. I really don't want any drama, but I need to say something.

I taped a note on there saying, "Is someone using my toothbrush?"

Is that too passive aggressive? If I ask they'll just deny it. What do I do?

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: My roommate and/or her boyfriend might be using my toothbrush. I'm mad. How do I find out for sure and have them stop? Do I ask?