Why forensic evidence can't be accurate

Police claim that a key piece of evidence against me were carpet fibers taken from the binding materials which matched carpet samples taken from my mother's home. This cannot be possible.
An article dated 2/2/2005 in the Seymour Daily Tribune refers to a scent dog named Emma who was deployed in the search for Katie soon after she became missing says:"Emma, a bloodhound, provided investigators with the general direction from the apartments Collman had visited to the Dollar Store, and from there is was evident that the walking trail became a car trail."This would indicate that Katie was abducted from the Dollar Store and not from my mother's home.
Another article printed in the Tribune on 1/27/2005 supports this. It states "Investigators, however have determined that Collman first visited a friend in an apartment west of the store, Ford said. Collman then went to the store and back to the apartment.
She was last seen walking North from the apartments, Ford said."
North from the Penn Villa apartment complex would have been in the general direction of the Dollar General Store.
My mother's house was Southwest of the apartment complex.
Now I ask, could it be possible for 16 carpet fibers to have remained on the girl's body after floating in a lake for over 5 days? Not at all likely. I beleive this evidence was taken by authorities from my mother's house.