When Michael Slager's murder trial starts next week, the presiding judge will have a fresh proposal to consider: a plea to dismiss the case entirely.

That's what attorneys for the former North Charleston policeman say should happen because state and federal authorities have been "double-teaming" Slager to prosecute him in Walter Scott's shooting death.

Their argument is based on a bid to upend the "dual sovereignty" doctrine, a precedent that has allowed both governments to prosecute someone if the alleged misconduct falls under their jurisdiction.

Slager's defense team on multiple occasions leading up to the trial have alleged authorities have been colluding on joint interviews of witnesses rather than investigating on their own.

"The double-teaming of Slager ... is a chilling example of how far politically motivated politicians and prosecutors will go to seek headlines and feather their own nests at the expense of a public servant ... who had to make a split-second life or death decision that will be second-guessed by comfortable armchair quarterbacks," defense attorneys Andy Savage and Donald McCune wrote in a filing this week. "This is unconscionable."

State Circuit Judge Clifton Newman decided not to take up the dismissal motion during a hearing Friday because prosecutors had not prepared an argument against it. But 9th Circuit Solicitor Scarlett Wilson took issue with the defense contention.

"I reject the notion that this is a joint investigation," she said. "While certainly there has been cooperation between the two, we are running parallel."

Slager, 34, is charged with a state murder count in Scott's shooting, which was filmed by a witness. He faces three charges, including a civil rights violation, in federal court.

The hearing was the last chance for opposing attorneys to bring up legal issues before jury selection Monday. Newman also heard arguments from an attorney for The Post and Courier, which has fought his decision to shut the public out of testimony last week by prosecutors about how state investigators have handled the case. The judge did not immediately decide that issue.

Slager has insisted he got into a fight with Scott, 50, after an April 2015 traffic stop and the motorist snatched his Taser and turned it against him. He fired in self-defense, he said, as Scott turned away. The bystander's video showed Scott running when Slager fired eight shots, hitting him five times from behind.

Presented in a 23-page motion, the defense's long-shot request for a dismissal is based largely on constitutional protections from double jeopardy, the concept stating that criminal defendants cannot be prosecuted twice for the same crime. Miller Shealy, a former federal prosecutor, is expected to orally argue in favor of the motion once the trial starts.

As evidence of the authorities' close cooperation, the motion included an email from Assistant U.S. Attorney Eric Klumb that said federal prosecutors' evidence is largely the same as the state's.

The filing also revealed federal prosecutors had offered Slager a chance to plead guilty before they even sought his indictment, in exchange for dropping a gun charge that carries a 10-year minimum sentence. Slager didn't take the offer and was indicted two weeks later.

As a result, the defense lawyers said, Slager was being "crushed by the logistical, financial and fiscally frivolous policy of simultaneous prosecution."

But the issue most discussed Friday was whether the judge should have closed a hearing last week.

Jay Bender, the attorney for The Post and Courier, told Newman the public should have the opportunity to evaluate authorities' performance in the case by having access to testimony about that performance.

At the hearing, the defense raised questions whether State Law Enforcement Division agents had lied to Slager's first lawyer to get him to agree to an interview. Savage, the attorney now leading the defense, sought to determine what Wilson and Chief Deputy Solicitor Bruce DuRant knew about that deception. Savage cited legal precedent in a case called State v. Quattlebaum for allowing prosecutors to testify in a closed-door proceeding.

Without discussing his reasons, the judge ejected most members of the public. The Post and Courier objected.

Bender stepped in later, asking the judge to reconsider the closure and, to make up for it, allow a transcript of the testimony to be made public. He said constitutional provisions favor openness and that the precedent did not require prosecutors' testimony to happen in private.

"The public has every right to evaluate how its institutions perform when there is a challenge to the performance," Bender said.

Wilson argued that much of her own testimony wasn't relevant to the issue being probed by the defense and should be removed from the transcript if it's released. That release also would be problematic during the trial, she said.

"At this point, it will beg more questions than it answers," she said. "I have no interest in hiding anything from the public, but timing is everything."

Before saying he would consider the arguments, Newman said he would have to weigh them against Slager's right to a fair trial.

"You'll find no stronger advocate for open courts than me," he said. "I fully support ... the public's right to know."

Other developments Friday:

  • At least 188 possible jurors will show up Monday for jury selection. About 600 had been summoned.
  • The judge said he didn’t plan to sequester the jurors. The move could be “overly burdensome,” keeping them away from loved ones at election time and with holidays nearing, he said. 
  • McCune expressed concern that the amount of evidence recently received endangers the defense team’s ability to be ready for trial. Prosecutors turned over 2,800 pages and a 32-gigabyte flash drive recently. The discovery of a "diamond in the sand" while sifting through that information could hamper the defense's ability to be ready for trial next week, McCune said. Wilson said she had tried to be forthcoming with all evidence, but that she only recently learned about tests being done by investigators in secret. It was revealed last week the State Law Enforcement Division had conducted tests on marks on Slager's uniform the defense says are consistent with a Taser.

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Reach Andrew Knapp at 843-937-5414 or twitter.com/offlede.

Andrew Knapp is editor of the Quick Response Team, which covers crime, courts and breaking news. He previously worked as a reporter and copy editor at Florida Today, Newsday and Bangor (Maine) Daily News. He enjoys golf, weather and fatherhood.