What standard of proof is required for the admission of prior testimonial statements under the forfeiture-by-wrongdoing exception to the Confrontation Clause?

QUESTION PRESENTED The Sixth Amendment’s Confrontation Clause forbids the use of prior testimonial statements that were not subject to cross examination against a defendant at a criminal trial unless those statements fall into one of the narrow exceptions. In this case, the district court permitted the prior grand jury statements of Hasan Williams identifying Telly Hankton has the killer of Jesse Reed under the exception to the Confrontation Clause. Within days of Hasan Williams’ grand jury testimony, a man named Walter Porter killed Hasan Williams. Telly Hankton was in jail at the time of Williams’ killing and did not know that Williams had spoken to police or testified before the grand jury. Nonetheless, the district court found that Williams’ grand jury statements against Telly Hankton could be used against him at his trial, because he had “acquiesced in wrongfully causing” Williams’ unavailability as a witness, and did so intending that result. To address the lack of evidence of forfeiture by wrongdoing, the government’s argument in the district court relied upon conspiracy liability theory, a doctrine which has split the federal circuit courts. Considering the dearth of evidence establishing the Confrontation exception of forfeiture by wrongdoing and the government’s reliance on conspiracy liability theory in the district court, this case thus presents the following question: 1. By what standard of proof does the Sixth Amendment permit the admission at trial of prior testimonial statements under the forfeiture by wrongdoing exception to the Confrontation Clause? 2