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Just days before the courtroom showdown between the Justice Department and Apple over a locked iPhone used by the man behind the terrorist attack in San Bernardino, Judge Sheri Pym has allowed both sides to cross examine witnesses, offering the parties a chance to challenge the sworn statements offered by their experts.

In a call with reporters Friday, Apple’s attorneys said Judge Pym was asked by the Justice department to allow for witnesses to be called during the hearing, a move the attorneys characterized as strange and last-minute, but said they nonetheless supported, to grant the court a more complete presentation of facts. Last month, Pym ordered Apple to help the FBI break into the encrypted device by designing new software that would defeat several security features built into the iPhone. Apple has challenged Pym’s order, and the hearing was arranged to settle the dispute.

The addition of witnesses adds an element of unpredictability to the hearing, a move that could invite contentious exchanges during cross examination, or a more in-depth technical discussion of the case's intricacies.

The Justice Department will have the opportunity to cross examine Apple’s manager of user privacy, Erik Neuenschwander, and Apple’s lawyer who handled the government’s legal requests during the initial investigation in San Bernardino, Lisa Olle. As part of Apple’s legal challenge to the court order, Neuenschwander and Olle previously offered sworn statements to the court.

Neuenschwander had addressed the security concerns that would arise from the new operating system, and cast doubt on the government’s claim that the new software would only be used once, characterizing the Justice Department’s rationale as “fundamentally flawed.” Olle spoke to Apple’s potential legal and technical burden. If Apple were ordered to comply, she stated, similar requests for security-suppressing software would pour in, forcing the company to employ legal and engineering teams whose sole purpose would be to comply with government orders.

If it chooses, Apple can cross examine two FBI technicians, Christopher Pluhar, and Stacey Perino. Both have indicated that the FBI has exhausted its technical capability to access the data stored on the iPhone in question. Their statements have been used by the government to support the claim that Apple alone retains the power to help unlock the device. Perino and Pluhar have also challenged Apple on the ability of the FBI to recover information stored on the phone through an iCloud backup.

Shortly after the iPhone was seized by the government, the FBI had the iCloud password linked to the device reset. Apple insists that had the password not been changed, a backup of the phone could have been made by connecting the device to a trusted Wi-Fi network, like Farook’s home, without having to enter the phone’s passcode. The government maintains that this method would not have worked because, as Perino States, “a cold-booted iPhone will not connect to WiFi networks trusted by the Subject Device such as a home or work network until the passcode is entered.”

At the in-person arguments next week, the issue of the password reset is likely to be a major point of contention, as it has already through court filings. In Apple’s latest brief — the last court filing before the hearing — the company cited FBI Director Comey’s testimony in front of Congress, where he described the password reset as a mistake. In court documents, however, the Justice Department described the reset as a “reasoned decision.”

“A forced backup of Farook’s iPhone was never going to be successful, and the decision to obtain whatever iCloud evidence was immediately available via the password change was the reasoned decision of experienced FBI agents investigating a deadly terrorist conspiracy,” the government has stated.

Apple and the FBI’s experts have also disagreed on whether an iPhone customer is able to disable iCloud back ups for individual Apple apps — mail, photos, notes, for instance. Apple’s Neuenschwander has described the statements of the FBI’s Pluhar and Perino as “incorrect” containing “several mistakes,” “false” and said of Pluhar that he was “likely looking at the wrong screen on the device,” when assessing the potential for an iCloud backup.

Apple’s lawyers said the hearing will begin with introductory comments from Judge Pym, followed by ninety minutes or so of witness testimony, and then about ninety minutes of legal arguments — with Apple going first and last, and the Justice Department presenting in the middle.

Because the San Bernardino investigation is ongoing, Apple’s lawyers said they have been restricted by confidentiality requirements to limit what they can say in public about the case. But since the Justice Department has requested that expert witnesses in the case be questioned during the hearing, Apple’s lawyers said they hope these restrictions will be relaxed to more fully inform the court.

The Department of Justice declined to comment.