Audio problem during video record - can it be corrected?

I recently taped a class on a  Sony Digital Camcorder.  I have done this before and edited the video using Adobe Premier Pro CS6 for our website.  Usually I have no problems.  This time however, about  a minute and a half in something happens to the audio and it sounds like the professor is using one of those B movie devices to alter the kidnappers voice, really freaky.  I have tried a few things in Audition, but I don't know enough about the program or what might be wrong to fix it.  Anyone out there have any advice on how to correct this, if possible?  I would hate to have to tape another class and of course the info won't be the same.    I looked for help online, but nothing really seemed to describe what I could identify as my problem.  I tried a few pitch adjustments and they helped, but not enough. When I view the audio using Audition Spectral Pitch Display, I can see exactly where whatever happened, happened.  I have included a picture of that.  Any help would be appreciated.