A former Hawaii prosecutor talks to PEOPLE about the "strong" case against Alexandria Duval in the death of her twin sister, Anastasia

This fall, Alexandria Duval will be tried for the murder of her identical twin sister, Anastasia. Last spring, both women were inside an SUV that fell 200 feet after careening off a cliff in Hawaii.

Alexandria, who was behind the wheel, survived the deadly crash — which prosecutors insist was murder.

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But how hard will it be for them to convince a jury? A former Hawaii prosecutor, who is unconnected with the proceedings, tells PEOPLE he believes the case against Alexandria is “strong.”

“There was enough … probable cause to believe this lady knowingly committed this crime,” explains Peter Carlisle. “Obviously, every fact is going to be critical in this case.”

“There’s an accumulation of factors that have to be considered by the jury once they are given the charge to deliberate by the court,” he continues.

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Alexandria, born Alison Dadow, learned in November that she would be charged with murder in the death of Anastasia (née Ann Dadow). Authorities allege she intentionally steered herself and her sister off a cliff in Maui, Hawaii, on May 29, 2016.

Eyewitnesses who were driving behind their vehicle told police that Alexandria and Anastasia appeared to be fighting and that Anastasia could be seen pulling her sister’s hair, officials have claimed. (Prosecutors declined to comment to PEOPLE about the case.)

“You also have eyewitnesses who saw the driver take a sudden sharp turn into the rock wall and continue off the cliff,” Carlisle tells PEOPLE.

“She is driving, she is in control, and she went off the cliff,” he says. “Witnesses said she appeared to be in a rage, that the woman in the passenger seat was pulling the hair of the driver.”

Image zoom

Image zoom Alexandria Duval in court in November 2016. AP Photo/Mike Groll

Alexandria has pleaded not guilty to the murder charge and is free on bail. Her attorney tells PEOPLE the crash was a “tragic accident” that has “devastated” her.

But Carlisle says the state will likely also call out Alexandria’s alleged attempt to flee Hawaii days after her sister’s death. She was found in upstate New York on Nov. 11, a month after a warrant was issued for her arrest.

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“She tried to board a plane on June 1 to the West Coast,” Carlisle says. “The prosecution will likely infer she was fleeing the jurisdiction to escape the consequences of conviction. The prosecution may argue that that attempt to flee suggests consciousness of guilt.”

If convicted, Alexandria will automatically receive a life sentence, according to Carlisle.

Image zoom Anastasia (left) and Alexandria Duval in 2011.

“The question really becomes what type of evidence will be important,” he says, noting both direct and circumstantial evidence can be presented during murder trials in Hawaii.

“Jurors can give equal weight to both kind of evidence,” Carlisle says, “and the circumstantial evidence here is every bit as strong as the direct evidence.”

However, jurors could consider a lesser offense.

“The charge could be downgraded from murder to manslaughter, which would mean a 20-year sentence,” Carlisle says. “It’s all going to depend on the quality of the testimony and the witnesses who take the stand.”