The prosecution urged the judge to believe the confession Joyce McLain’s accused killer made to his pastor, his parents and a co-worker and not consider how long it took police to charge him.

The defense argued that the state had not proven Philip Scott Fournier’s guilt beyond a reasonable doubt and was hinging its case on one small piece of nearly 36 years of investigative work — statements made after the defendant suffered a traumatic brain injury.

Fournier, 57, of East Millinocket was charged with murder in the teenager’s 1980 death in March 2016. His jury-waived trial concluded Monday after 9½ days of testimony before Superior Court Justice Ann Murray at the Penobscot Judicial Center in Bangor.

Murray said that she would issue a written verdict “in due course,” but did not set a date for her decision to be announced.

McLain’s mother, Pamela McLain, and other family members left the courthouse Monday without speaking with reporters. Pamela McLain, who has advocated over the years that the investigation into her daughter’s death remain active, rode away in an East Millinocket police cruiser. She testified the first day of the trial about the last time she saw the girl alive and about the subsequent search for her after she went missing.

Sixteen-year-old McLain was last seen alive about 8 p.m. Aug. 8, 1980, jogging near Schenck High School in East Millinocket. Her partially clad body was found about 6 a.m. Aug. 10, 1980, behind the school’s athletic fields. The back of her skull was caved in, and her hands were tied behind her back with a blue cloth.

About 3 a.m. on Aug. 9, 1980, Fournier burglarized a local garage and stole a fuel truck. He crashed into a passenger vehicle less than a mile away in Medway and suffered a skull fracture. The defense said again Monday that Fournier’s injury that night made his statements over the decades unreliable.

The resulting traumatic brain injury caused Fournier to confuse his own memories with things he’d been told, dreamed or imagined, Dr. Robert Riley, a clinical neuropsychologist in Augusta testified last week for the defense.

In May 1981, Fournier told his pastor and parents that he killed McLain, according to trial testimony. He repeated the confession to investigators the same day but was not arrested. Fournier later recanted that confession.

“He has not once denied telling his parents or pastor what he had done,” Assistant Attorney General Leane Zainea told Murray. “But once he told them he killed Joyce, he’s been backtracking ever since.”

She said that when he confessed to the Rev. Vinal Thomas, Fournier revealed a detail that only investigators knew: McLain was having her period when she died. The retired minister testified last week that when he asked Fournier if he’d had sex with McLain, he said, “No. It was the wrong time of the month.”

No evidence was presented at the trial that McLain was sexually assaulted.

The prosecutor conceded that there was no forensic evidence tying Fournier or anyone else to McLain’s body, her clothing, the electrical insulator or the rock found near her body.

Defense attorney Jeffrey Silverstein of Bangor told Murray that the state was basing its case entirely on Fournier’s alleged confession.

“The state has taken a small piece of years worth of work and less than ample evidence and said, ‘Let’s go with what we got,’” Silverstein said. “[Prosecutors] are trying to fit a square peg into a round hole, and it is a loose and sloppy fit.”

The defense pointed to at least four alternate suspects but did not call any of them to testify. One is deceased, two now live out of the country, and the fourth, who was seen with Fournier the night of the murder, invoked his Fifth Amendment right not to testify at hearing in July 2016.

The prosecution has not identified a murder weapon or offered witnesses who saw Fournier behind the school, Silverstein said. Witnesses did testify that they saw Fournier in front of the school that evening.

“This is not a recipe for proof beyond a reasonable doubt,” the defense attorney said, in summing up the prosecution’s case against Fournier.

In her rebuttal Monday, Zainea told Murray that the lack of forensic evidence doesn’t mean Fornier is innocent.

“The fact that no DNA linked McLain’s body to anyone does not change the fact that the defendant told his mother, ‘Mama I know what I did. I killed Joyce McLain. I knew it was wrong,’” the prosecutor said.

Zainea also pointed to Fournier’s reported confession in 1989 to his supervisor at Husson College where he worked for a year as a janitor.

“The defendant bragged about beating the interviews with law enforcement and that’s pretty much what’s happened over time,” she said.

Silverstein said outside the courthouse that he does not expect Murray’s decision to end speculation about how and why McLain died.

“I think this case resolves very little, if anything,” the lawyer said. “Whether [Fournier’s] convicted or not, there still remains great doubt. The state police have not revealed all of the evidence [about alternate suspects]. The whole story has not been told and doubts will linger about this case regardless of what happens.”

Since being arrested on the murder charge on March 4, 2016, Fournier has been held at Penobscot County Jail in Bangor, unable to post $300,000 cash bail.

If convicted of murder, Fournier faces between 25 years and life in prison.

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