Invisible fire, that what ever you do, it won't go out.

I accidentally set the ground on fire and turned off fire spreading so I could get rid of the fire easily, once the fire was all put out there was still a cackling sound. If I walk over this certain patch of land I get set on fire and also take damage, but there is no visible fire. I have tried water and also destroying the block and placing blocks on the land that I believe it's on, but it will not go away. I have also tried turning back on fire spreading and also turning friendly fires back off but still is nothing. I also had someone else join the world to see if they can see it and they couldn't. Please help me