Sketchy people trying to set our house on fire?

This is a weird topic- I don’t know where else to ask this though 🤷🏼‍♀️ So we rent out our guest bedroom on AirBnB, we have a couple staying in it this week. When she booked it was a little sketchy, she messaged me at 8pm and said she was sitting at Starbucks with her husband, her friend was going to host them but fell through. She needed somewhere for the next 8 days. She only had $240 and asked if I would accept that. I figured they were just in a tough spot, so I said yes. Then they didn’t show up until 6 hours later, the middle of the night. ?. That was two days ago. Last night they didn’t come home until the middle of the night too.

Now, this morning at 7am, my husband and I are asleep, I wake up hearing the fire alarm going off on the other side of the house. I shake my husband and say “there’s an alarm going off, can you go check it out.” He goes out of the bedroom and then comes back in and says “it’s coming from the guest room, I don’t know if I should go in there?” So he goes and knocks on the door and the guy opens the door and a massive fog of smoke comes out. He says calmly “sorry man, we lit a candle. I tried to put it out but I burnt myself.” Something about that story doesn’t make sense? “Put out” a candle?

My husband came back and he stared blankly at me and said “honey. I don’t know what’s going on in there, but it’s weird.” There was a candle on a shelved nightstand and he said there were like white sticks in the candle...?

I don’t know if maybe something caught fire and they were embarrassed to tell us? What would cause that much smoke? I’m thinking maybe it burnt the shelf? The smoke smelled horrible too. The whole house stinks and it’s making me want to throw up.

Anyone know what might be going on?

If it’s just an honest mistake and something is burnt then it’s really no big deal. I’ll just charge a damage fee. But like, are they doing some kind of religious service in there??? or drugs??? 😂 wtf