When Abraham Reynolds is shoved to the ground, he lands with his head on top of the curb. All subsequent shots show his entire body on the ground, with his head next to the curb.
Maura said the flower petal they found at the scene of the murder had traces of volatile chemicals. The word volatile is used for substances that evaporate away completely so there would be no trace of them, and certainly not after twenty-four years.
Maura says the brown substance she analyzed was paint and that it contained highly volatile Naphtha. Naphtha is a solvent that is an ingredient in paint thinner and evaporates away completely as the paint dries. No trace of Naphtha or any other ingredient in the thinner are left behind so there would not be any trace of them in the dry paint.