An attorney for a man charged with a killing last summer in downtown Minneapolis is asking a judge to throw out the case after a key defense witness was killed late last month.

The defendant, James Wren, 36, is accused of firing the shots that killed Michael Clark and left his nephew paralyzed from the waist down after an altercation in a parking lot behind Augie's Cabaret and Sneaky Pete's last June. He was later indicted by a grand jury on first-degree murder, and the trial date was set for March 16.

But citing caution over COVID-19, prosecutors asked for, and were granted, a continuance that pushed the trial back to May — a delay that Wren's court-appointed lawyer argues violates his right to a speedy court proceeding.

"The motion (for continuance) was opposed by Mr. Wren — after all, the trial date was at hand, a jury had been gathered, a questionnaire was completed and reviewed," assistant Hennepin County public defender Bryan Leary wrote in a court filing, urging the judge to consider releasing his client under supervision pending trial.

Then, on March 22, a witness in the case, Kyle Culberson, was killed when a gunman opened fire on a birthday party at a house in north Minneapolis' Shingle Creek neighborhood, striking Culberson and two others. Last week, Christopher Brown, 23, was charged with a single count of second-degree murder and two counts of attempted second-degree murder in the shooting. He remains in jail in lieu of $1 million bond.

Culberson is listed in court filings as a potential witness for both the defense and the state, but his connection to the Wren case was first disclosed in court documents made public last week. Authorities have given no motive for his slaying, but there is no indication that Culberson — who is listed as a potential witness for both the defense and the prosecution — was targeted because of the testimony he was expected to provide.

But Leary asked to have the case against Wren thrown out, arguing that the loss of one witness and the alleged threats made against others have unfairly prejudiced his client's case.

"Now, trial is set to begin on May 11, 2020, but will yet the delay and recent events (beg) the question: will any of Mr. Wren's witnesses still be alive then?" Leary wrote. "The world is in a far different and far worse place now — emotionally, medically, economically, astrologically, and spiritually — than it was in October 2019, when a speedy trial was demanded."

A police spokesman on Tuesday said that he couldn't discuss either murder case, because they are pending in court, and referred further questions to the Hennepin County Attorney's Office. A spokesman for the office said that prosecutors have until April 15 to file a response, but wouldn't comment otherwise on the case.

When reached by phone on Tuesday, Leary declined to discuss the case, saying the filings speak for themselves.

According to police reports, surveillance video captured Wren and Culberson walking into Augie's in the early morning hours of June 10, then leaving about half an hour later. Once outside, a confrontation broke out between Wren and Clark's nephew and another man, who police later learned was armed and had a permit to carry. Police say that Wren opened fire, striking the nephew and Clark, who had stepped in to intervene.

Wren tried to escape on foot and was arrested a short time later, but no murder weapon was recovered at the scene, the reports say.

St. Paul police recovered a .357 Glock handgun that investigators suspect was used in the shooting during a traffic stop on the city's East Side last December, but officials said that further ballistics testing is needed.

Officials say that the killings of witnesses isn't as large of a problem in Minneapolis as it is in other cities, but they do happen.

Court filings show that a former Native Mob member was shot in 2017, and survived, apparently in retaliation for his testimony in a federal drug and weapons case that resulted in the sentencing of 28 of his fellow gang members. Witnesses in the 2017 fatal shooting of Iesha Wiley and the slaying of Birdell Beeks a year earlier were also killed according to police and court documents. In the latter case, fingerprints taken from the scene matched those of Low End gang member with a reputation as a "shooter," but neither he nor anyone else has ever been charged in the crime.

Leary argued that Culberson's expected testimony would have corroborated Wren's self-defense argument. Leary said that now other witnesses in the case are having second thoughts about taking the stand.

He admitted that some of the blame for the delay lays with Wren, who originally filed a motion for a speedy trial on Oct. 3. At the time, the trial was set for Jan. 21, with a backup date of March 16 should Wren be indicted, which he was. After switching attorneys in November, Wren agreed to keep the March backup date, and agreed to waive his speedy trial rights until then, according to defense filings.

As COVID-19 continues its rapid spread, judges, prosecutors and defense attorneys are confronted with the task of deciding when to lock up people and for how long, amid growing fears of spreading the virus behind bars, according to Richard Frase, a professor of law at the University of Minnesota. But the unprecedented challenges created by the pandemic puts the case in uncharted legal waters, he said.

"He's not the only person who's going to be making a speedy trial motion because of the problem of not wanting to put people together in the courtroom," Frase said of Wren, adding that the ongoing pandemic "forces everybody to take another look at who's in detention and ask if they really need to be there and what are the alternatives.

Frase said that while the defense has a strong argument under the state's speedy-trial law, which limits the amount of time between a defendant's arrest and trial to 120 days, the state could argue that the delays were beyond its control.

But Leary, the public defender, says that each extra day that Wren spends behind bars puts his client further at risk of infection.

"As weeks and months have passed, Mr. Wren has stayed in a cage, exposed to a seasonal flu epidemic that swept through the jail. Now, Mr. Wren is made to bide his time in that veritable petri-dish," Leary wrote. "With overcrowding, and little to no room to truly separate inmates if symptoms arise, are quarantine methods at the jail a realistic safeguard? No one knows."

Libor Jany • 612-673-4064 Twitter: @StribJany