Chance. The same bureau that has a long track record of destroying its victims exculpatory evidence, altering FISA docs, as well as destroying evidence of the bureau and its political friend's wrongdoing would not hesitate for a second to fabricate evidence out of whole cloth.
This isn’t new news
http://crimemagazine.com/tainting-evidence-inside-scandals-fbi-crime-lab
And let’s not forget about: Ruby Ridge, Waco, and what they did to Lavoy Finicum