HARRISBURG, Pa. (AP) — A man on death row for killing one Pennsylvania state trooper and wounding another to act out his anti-government beliefs wants the state Supreme Court to throw out his conviction.

Lawyers for Eric Frein and Pike County prosecutors are scheduled to argue before the justices in Harrisburg on Thursday, nearly four years after the killings and subsequent 48-day manhunt in the Pocono Mountains.

Frein, 35, killed Cpl. Bryon Dickson II with two shots fired from the woods near the Blooming Grove state police barracks in September 2014, and wounded Trooper Alex Douglass so badly he has needed at least 18 major surgeries.

Frein's lawyers argue interrogators violated his right to remain silent and should have permitted him to speak with a defense lawyer his family retained the night he was captured. The lawyer was kept outside during three hours of questioning in which Frein confessed.

"The questioning at issue occurred after Mr. Frein was read his Miranda warnings, invoked his right to silence by clearly informing the troopers that he did not want to speak about any crime and refused to sign a Miranda waiver," his lawyers argued in a brief filed in November.

They also say the trial judge allowed too much testimony about the impact of his crime during sentencing, 10 witnesses over two days, describing it as "emotionally charged, cumulative and much more prejudicial than probative."

In a response two months ago, the Pike County district attorney's office said that even if Frein did assert his right to remain silent, he initiated a conversation about the crimes with a pair of state police investigators.

The trial judge has written that Frein's statements about not wanting to get too far into the matter or discuss crimes were ambiguous, given that he was willing to speak with the troopers about the location of a gun he had buried in the woods.

Prosecutors also said federal and state case law has held that police do not have to provide a defense lawyer with access to a suspect as he is being interrogated unless the suspect asserts his right to legal representation. And they said Frein has not shown how the victim impact testimony harmed him during the sentencing phase.

Frein was identified as a suspect soon after the shooting, in part because a neighbor noticed his vehicle had been abandoned after becoming stuck in a drainage pond not far from the murder scene. Frein left his wallet inside the vehicle.

In a letter to his parents written while he was hiding out, Frein said he did not "know what the revolution will look like or even if it would be successful."

Prosecutors have said Frein spoke of wanting to start a revolution and described Dickson's slaying as an "assassination." Frein allegedly said he wanted to "wake people up" and "make a change (in government)."