I'm researching about this natural physichal/chemical phenomenon, which is known to occur where organic material undergoes natural decomposition.
The phenomenon is rare, is seen only in the dark (which means only night time) and is observed mainly in marshes, swamps, cemeteries (in the past) or wherever some decaying material is present under ground or water.
If you have experience or recent observation of this light phenomenon, which is normally described as a transient "cold flame", please contact me.
I'm collecting reports about this fact, and any recent sighting will be very helpful for my research.