The visitors needed to take three points and hope that results elsewhere went their way if they were to have any chance of survival.
But after taking the lead in the first half through striker Simeon Jackson, they were unable to hold on and the defeat at Elland Road finally confirmed their relegation, although a win would not have kept them up anyway.
Leeds looked uneasy at the back in the opening stages and Paul Huntington gifted the visitors a crucial opening goal after 20 minutes when his attempted backpass to keeper Casper Ankergren was cut out by Jackson, who tucked the ball confidently into the right-hand corner of the net.
The home side eventually scored in the 69th minute when Seb Carole's cross picked out Bradley Johnson, who struck a sweet, left-footed volley past the helpless Derek Stillie into the bottom corner.
And Leeds stole all three points and broke the travelling fans' hearts with just two minutes remaining when Kandol raced onto an incisive throughball from Andy Hughes and flashed a powerful finish past Stillie to settle it.