I need to be able to take the evidence from a battery leak of D batteries and determine if it was Alkaline or Zinc-carbon batteries that were installed. The leak was wet and gooey, and the contacts on the device it were in were also damaged. Are there any particular signs and determining evidence to look for to differentiate the two?

Potassium hydroxide leaks from Alkaline batteries and form a feathery crystalline structure…. check the "leak" section of this wikipedia page:

http://en.wikipedia.org/wiki/Alkaline_battery

I would call or bring the device to Batteries Plus… They should be able to tell you for sure.

Batteries Plus phone number is: 1.800.677.8278

Website: http://www.batteriesplus.com