Favorable evidence is any evidence that if disclosed and used effectively may make the difference between conviction and acquittal. See Bagley, 105 S. Ct.at 3380; Thomas v. State, 841 S.W.2d 399, 404 (Tex. Crim. App. 1992). Favorable evidence includes both exculpatory and impeachment evidence. See Thomas, 841 S.W.2d at 404. Exculpatory evidence is "evidence which tends to justify, excuse or clear the defendant from alleged fault or guilt." Id. Impeachment evidence is evidence offered to dispute, disparage, deny, or contradict relevant evidence. Id.