Bullet FL is a bullet found under a compressor in Steven Avery's garage. It was designated as "FL" by the Wisconsin Crime Lab. DNA of Teresa Halbach was found on the bullet. The bullet was matched to a .22 caliber rifle that Steven had hanging above his bed.
While examining the bullet Sherry Culhane of the Wisconsin Crime Lab contaminated the control sample and inadvertently brought her own DNA in the sample. The result of the test should therefore have been inconclusive. But because of the importance of the result and because Culhane was still able to determine the two samples individually (they had not mixed) the results were allowed at trial.