What did Dumbledore suspect of Harry during their conversation in Harry Potter and the Chamber of Secrets?

Question

‘I must ask you, Harry, whether there is anything you’d like to tell me,’ [Dumbledore] said gently. ‘Anything at all.’

_{Chamber of Secrets - page 156 - Bloomsbury - chapter twelve, The Polyjuice Potion}

What did Dumbledore suspect of Harry during their conversation in Harry Potter and the Chamber of Secrets?

Dumbledore said "I must ask", as opposed to, for example, "I was wondering" or "How are you doing? Is there anything on your mind that you need to talk about?" The use of "I must" suggests a bit of urgency, and perhaps some kind of obligation on Dumbledore's part.

Is there any indication that Dumbledore had a particular topic in mind when he questioned Harry, or was it just a general inquiry? Does canon address this at all, even in the later books?

Answer 1

There's no canon info on what he suspected specifically. We can only guess:

1. He knew that Harry was up to some mischief.

   Leaving aside that Harry always attracted trouble in general, in these events, as Snape put it after Ms Norris was petrified:

   'Potter and his friends may have simply been in the wrong place at the wrong time,' he said, a slight sneer curling his mouth as though he doubted it, 'but we do have a set of suspicious circumstances here. Why were they in the upstairs corridor at all? Why weren't they at the Halloween feast?'

   Remember that Dumbledore knew that Harry had the cloak, and could be hoping that Harry knew something or observed something. He also had experience of Harry finding stuff out from Year 1.

2. In addition, he most likely knew that Harry knew something, merely by the virtue of being a 100+ old wise, experienced old teacher dealing with an earnest Harry Potter, aged 12.

   Remember that this is the same man who figured out Tom Riddle was lying about Hagrid and the Chamber, when it was last open. Harry was far less of an accomplished lyer.

3. To address OP's "must" concern, I read that as simply Dumbledore being incredibly concerned and determined to pursue any and all leads and chase all available avenues, and as per my bullet #1 and #2, he definitely had enough reasons to think that asking Harry is a worthwile lead.

TL;DR: He suspected Harry of knowing more than what he (Dumbledore) knew about the events transpiring.

Answer 2

Well at the time, Dumbledore knew that Harry had been suspected by most of the school for being involved in the attacks. Add to that Dumbledore cares greatly for Harry (Explained in The Order of the Pheonix) and is sensitive to his feelings.

Dumbledore probably used the word "must" because he was trying to stop himself from caring too much about Harry but felt compelled to check up on his well-being.

Answer 3

Also, see it from Dumbledore’s perspective. Harry has shown up first to several of the attacks. So, obviously he is privy to something no one else knows about.