I tend to side with caution on eye witness reports. It may well be that we have experienced police and fire crew but they are not observing and RTA or building fire.
Also, if the a/c was already on fire, their eye would naturally be drawn to that, they would not expect the tail fin to have gone and the question: "Was the tail fin still in place, when you saw the a/c?" might not bring a reliable answer. They (like all/most of us) would never have seen an a/c without a tail fin and the 'usual' image of an a/c in flight might be stronger in their memory ...
On a lighter but related note, I recall reading many years ago, an article about the reliability of eye witness reports. One observer of an a/c impact (no details were given) would not sign his statement until the following words (in italics) were included.
"When he [the pilot] got into difficulties, I heard him give it the gun but he still went in."
The witness insisted on these words because he believed them to be the term that pilots use for applying maximum power. Very sad.
If I am unfortunate enough to witness a prang, I hope that I will think very carefully about what I saw and what I thought I saw.