Cain, played by Jeff Hordley, gets his comeuppance tomorrow night when one of his enemies brutally attacks him in a shocking act of revenge.
Yesterday, the Dingles were joint favourites alongside the Pollards with odds of 5/2 that any member of either family would be the culprit.
However, the Dingles have since pulled ahead as the clear favourites as bookmaker Victor Chandler cut their odds to 9/4 overnight.
The shift came after last night's Emmerdale episode saw a furious Debbie Dingle (Charley Webb) cut all ties with Cain, which could have contributed towards the change.
Meanwhile, the bookies now believe it is less likely that the attack will be carried out by a member of the Sharma family, as they have been pushed out from 7/2 to 4/1.
Show bosses have named John and Moira Barton (James Thornton and Natalie J Robb), Jai Sharma (Chris Bisson), Charity Tate (Emma Atkins), Amy Wyatt (Chelsea Halfpenny) and Zak Dingle (Steve Halliwell) as the main six suspects in the case.
Emmerdale airs Cain's 'Judgement Day' tomorrow night from 7pm on ITV1.
> Emmerdale announces shock whodunit storyline
> Emmerdale mystery: Who will attack Cain? - Poll
> Emmerdale star James Thornton to leave soap
> Emmerdale: John, Amy are top suspects in Cain mystery
> Emmerdale James Thornton promises "dramatic" exit
> Emmerdale: Cain's attack aftermath revealed - Unseen Pictures
> Emmerdale Cain in hospital after attack - Pictures
> Emmerdale star Jeff Hordley reveals Cain plot secrecy
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