application for the writ proffer the substance of the potential witness’ testimony. Id. Because the application did not contain a proffer, the district couif did not err in denying it. Finally, Santos and Rodriguez contend that collateral estoppel precluded the district court from finding that Santos was aware of Guerra’s illegal activities and thus not protected by the innocent owner defense. Because Santos was acquitted of the charges against her in the criminal case, Santos and Rodriguez assert that the fact she did not know of her daughter’s criminal activities has already been litigated and the result was binding on the district court. This argument is unsound. See One Lot Emerald Cut Stones & One Ring v. United States, 409 U.S. 232, 235, 93 S.Ct. 489, 493, 34 L.Ed.2d 438 (1972) (<HOLDING>). It is also irrelevant. The district court
holding to the same effect holding that a prior acquittal does not preclude the admission of evidence of a defendants other alleged crimes in a prosecution for the bank robbery on the basis of collateral estoppel principles because    the prior acquittal did not determine an ultimate issue in the present case recognizing estoppel based on bank officers conduct holding that collateral estoppel is not available to a criminal defendant for a judgment of acquittal following a civil traffic hearing holding that a criminal acquittal does not have collateral estoppel effect on a later civil forfeiture proceeding based on the same conduct