SEATTLE – Citing a prosecutor’s misconduct during trial, the Washington Supreme Court on Thursday overturned the aggravated first-degree murder convictions and 420-year sentence of Darcus Dewayne Allen, who drove the getaway car after Maurice Clemmons fatally shot four Lakewood police officers in 2009.

In a unanimous ruling, the high court said the prosecutor repeatedly gave the jury an inaccurate definition about what it means to have knowledge of a crime and it negatively impacted the outcome, so Allen should be tried again.

Allen had claimed he did not know Clemmons’ intentions on the morning of Nov. 29, 2009, but the prosecutor told the jury that a person is an accomplice if he knows, or “should have known” what was about to happen or what just occurred.

Allen is the fourth person involved in the Clemmons’ shooting to have his conviction overturned.

On Dec. 24, the court reversed the convictions and sentences of Clemmons’ aunt, Letrecia Nelson, and friend Eddie Lee Davis. They were found guilty of helping Clemmons evade capture and possession of a stolen firearm. The justices ruled it was inappropriate for the trial court to impose exceptional sentences. In 2013, the Court of Appeals overturned the conviction of Douglas Davis, who had been found guilty of possessing a gun and a stolen firearm.

Pierce County Prosecutor Mark Lindquist maintains that Allen is guilty.

“The deputy prosecutor should have phrased his argument more artfully so it was not open to misinterpretation, but it was the evidence that convicted Allen, not the deputy prosecutor’s words,” Lindquist said in an email.

Once Allen is returned to the Pierce County Jail, the case will be set for a new trial within 60 days, Lindquist said.