Pointing to a controversial state standard about expert-witness testimony, a divided appeals court ordered a new trial for a man convicted of vehicular manslaughter in a high-speed crash that killed five people in 2013 in South Florida.

A panel of the Fourth District Court of Appeal, in a 2-1 decision, said key testimony from a Florida Highway Patrol officer should not been admitted under the expert-witness law. As a result, the court ruled that Jabari Kemp should receive a new trial after being sentenced to 30 years in prison in the deaths in Palm Beach County.

Judge Cory Ciklin, in a concurring opinion, called the accident an “unimaginable nightmare” that killed five people who “were innocent victims doing nothing else but going about their lives.” But he wrote that a new trial was required because it could not be shown that critical testimony from the highway patrol officer “was based upon legally sufficient facts or data that met the reliability and admissibility requirements” of the expert-witness standard.

“Make no mistake. The state may ultimately be able to produce sufficient testimony and present the evidence necessary to lawfully convict Jabari Kemp, thereby holding him legally accountable for the devastation that took place in 2013,” Ciklin wrote. “However, with the trial record that is before us, we have no choice but to hold that the state did not meet its burden in Kemp's first trial and that a new trial is warranted. The gravity of our ruling does not escape us.”

The decision came after years of legal and political battling in the state Capitol about standards courts should use in determining whether expert-witness testimony should be allowed in cases. Such testimony can play a critical role in cases involving scientific or highly technical issues.

Kemp's car was estimated to be traveling at 128 mph when it traveled down an Interstate 95 exit ramp and crashed into another vehicle carrying the five victims. He contended he had fainted before the crash, a factor that could be important in determining whether he should be convicted of vehicular manslaughter.

Prosecutors, however, tried to prove that he had tried to brake his car, which would cast doubt on his argument that he was unconscious. The key witness was Florida Highway Patrol Corporal Robert Dooley, an accident investigator who provided testimony about the evidence of braking.

In a dissenting opinion Wednesday, Judge Melanie May pointed to Dooley's years of training and experience in investigating accidents and wrote “there can be no doubt that Corporal Dooley was an expert in accident reconstruction.”

“As the trial court noted, the admission of Corporal Dooley's testimony was based on physics and momentum, which is scientifically reliable,” May wrote. “That evidence was admissible, and its weight was subject to defense counsel's cross-examination and closing argument. It was the jury's role to decide what weight to give the opinion.”

But the majority focused on what is known in the legal world as the Daubert standard for admission of expert-witness testimony, and cited a May decision by the Florida Supreme Court that required courts to use the standard.

The Legislature and then-Gov. Rick Scott in 2013 approved a law that required use of the Daubert standard, which is more stringent than the state's long-standing expert-witness standard known as the Frye standard. The law came after lobbying from business groups, who argued that a move to the Daubert standard would prevent “junk science” from entering lawsuits.

In 2017, however, the Supreme Court, which has the power to set court procedures, blocked the move to the Daubert standard. But after a major change in the makeup of the Supreme Court this year, the justices in May reversed course and effectively directed courts to use Daubert.

The majority opinion Wednesday concluded that Dooley's testimony did not meet the requirements of that standard.

“We conclude that the trial court abused its discretion in admitting expert testimony that did not meet the requirements of Daubert. … The expert's braking opinion was not shown to be based upon sufficient facts or data, was not shown to be the product of reliable principles and methodology and amounted to little more than a subjective and unverifiable opinion,” said the opinion, written by Judge Carole Taylor and joined by Ciklin.

As an indication of the changing nature of the standards, the same appeals court in early May — before the Supreme Court decision — ordered that Kemp, now 27, receive a hearing using the old Frye standard. That order did not go so far as to order a new trial.

Jim Saunders reports for the News Service of Florida.