Curse/black magic? Help?

No worries. Everyone starts at the beginning after all.

One thing to prepare for though, is if you bring it up, they may first be kinda peeved that their stuff has been looked at. I know it was innocent enough, but people assume, and by their perspective the first leap would be a simple one. they had stuff in a private space, that stuff was looked at. People tend to close their ears to everything else if they are sensitive about their space, or if they are sensitive about their practice. it happens a lot, especially with people who have been judged or discriminated before. It makes it easy to assume one is being judged again. So just prepare yourself for a touch of backlash if that fits their personalities when you bring it up, and do your best to be patient and calm in explaining what happened.

Maybe even sidestep the finding of the altar at first, and start off by just bringing up magic in general an see where the topic takes you. ^_^