Grogmar Ghrobash
'Tis better to be alone, then of bad company.
Okay. Fair enough. Dagmar is pretty darned credible when it comes to lore. But she's not here, right now.
Aside from the suggestion that Dagmar says the site might not always be right... can you point me to a source that tells me exactly when these events occurred?
I'm on my xbox so I can't post any links, but I can assure you UESP is very credible. What you found on the Skyrim wiki may very well be correct, I'm just saying for future references that you shouldn't rely on that site. Just look up 'The Markarth Incident' on google and click the one that has UESP on it. The site should provide you other sources reguarding the topic also in case you want to double check.