I'm not condoning the players actions, but have the Police got nothing better to do than investigate this. If they were to investigate every time somebody had a winning bet because somebody had a bit of inside information, they'd never have time to investigate anything else.
I use to work in a bookies in the late 70's and we use to get the odd tip on horses then, sometimes to bet on a particular horse, and other times not to bet on it that time because it was gong to be held back etc so that in the next race you would get a better price and it was likely to win, that tended to be good information
This still goes on now, an ex-colleague will ring up five minutes before a dog race and say "trap 6, in the 1123" etc. Off the lads will toddle, and sometimes they win, other times they don't. I don't get involved in the dogs because they have a mind of their own, whereas horses can at least be steered.
Poor bookies, my heart bleeds for them