How did Fudge know?

[hogwarts_harry78]

No: HPFGUIDX 47469

There's something that has been bugging me ever since I first read 
Prisoner of Azkaban, and I haven't seen it discussed before (I 
apologize if it has been, and I'd appreciate if someone could point 
me to the relevant thread). It's in the last chapter of PoA, at the 
end of the conversation between Fudge and Dumbledore in the hospital 
wing (British paperback edition, page 453):

"'And the Dementors?' said Dumbledore. 'They'll be removed from the 
school, I trust?'

'Oh, yes, they'll have to go,' said Fudge, running his fingers 
distractedly through his hair. 'Never dreamed they'd attempt to 
administer the Kiss on an innocent boy ... completely out of 
control ..."

Now, my question is: how does Fudge know that a Dementor tried to 
kiss Harry? Snape couldn't have told him that, because he says he has 
no idea what made the Dementors retreat, and he adds, "By the time I 
had come round they were heading back to their positions at the 
entrances ..." (page 417). Hermione and Sirius were unconscious by 
the time the Dementor tried to administer the Kiss. The only person 
who knows about the whole thing is Harry, and we know he hasn't told 
Fudge anything. So, how did Fudge find out? The only theory I can 
come up with is that he is indeed evil and that he was the one who 
ordered the Dementors to kiss Harry in the first place. Any other 
ideas? Or am I missing something obvious?

This is my first post, by the way, so I hope I did everything 
right. :)

Andi