On the train home he found a compartment with Harry and Hermione and Ginny and Luna and Neville, and within the first ten minutes the photograph had come out again — Neville's doing, who had been looking at it periodically since breakfast with the quality of someone returning to a thing he had not finished understanding.
'It has to be a student,' Hermione said, in the tone of someone who had been thinking about this since breakfast. 'The angle of the doorway photograph. A teacher would have chosen a more expected position. And the noticeboards in September — those were placed during the night, which means someone with access to the common rooms.'
'Or someone who knew how to get in,' Harry said, with the quality of someone who was not exactly lying.
'The noticeboards were in all four houses,' Hermione said. 'So whoever it was had access to all four common rooms. Unless they used the house elves.'
A silence.
'The house elves,' Ginny said, looking up.
'Delivered overnight,' Hermione said. 'On the trunks and desks. The elves did that. Which means the Witness has a working relationship with the kitchen elves. Someone who has spent time in the kitchens.' She paused. 'Someone who thinks about what they're documenting and why.'
'It could be anyone,' Harry said.
Hermione looked at him.
Harry looked out of the window.
Hermione looked at Ron.
Ron turned a page of his book.
Ginny, from the corner, was watching this exchange with the specific quality she had when she had reached a conclusion and was waiting to see if anyone else arrived at the same place.
Luna said: 'I think the Witness sees things other people do not think to look at. That's a specific kind of person. There aren't many of those.'
A silence.
'No,' Ron said. 'There aren't.'
He turned another page. Outside the window, Scotland gave way to England.
Two compartments down, the twins were audible.
'I'm telling you, Forge, it's a sixth-year or above,' Fred said.
'Fourth-year minimum,' George said. 'That feast photograph is not the work of someone who's been here less than four years. The technical quality of the photographs. Not being seen. They would have to know higher grade spells '
'Could be a Muggleborn,' Fred said. 'Someone who used Muggle photography.'
'The photographs move,' George said, with patient emphasis.
'Someone who learned both,' Fred said.
'Name one person who you know who could do this,' George said.
A pause.
'Fair point,' Fred said.
Ron did not smile. He read his book and watched the window and thought about the year behind him and the year ahead of him, and found that the balance between them felt, for the first time since June of last year, approximately right.