From: Kate Atkinson, "Case Histories"
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London: Transworld Publishers (Black Swan edition), 2005

p.79:

Investigating [while he was in the police] other people's tragedies and
cock-ups and misfortunes was all he knew. He was used to being a voyeur,
the outsider looking in, and nothing, but nothing, that anyone did
surprised him any more. Yet despite everything he'd seen and done,
inside Jackson there remained a belief -- a small, battered and bruised
belief -- that his job was to help people be good rather than punish
them for being bad.
[NP]
He left the police and set up the investigation agency after his
marriage disappeared in front of his eyes.