Mark Cardilli Jr. takes the stand on the fifth day of his murder trial at the Cumberland County Courthouse in December 2019. Brianna Soukup/Staff Photographer

A Portland man who was convicted of manslaughter in 2019 after shooting his sister’s unarmed boyfriend will get a new trial.

Mark Cardilli Jr. admitted he shot 22-year-old Isahak Muse to death during an argument at the Cardilli family home in March 2019, saying at his original trial that he was defending his family and his home.

Isahak Muse Carl D. Walsh/Staff Photographer

Yet Justice John O’Neil ruled Tuesday that Cardilli’s trial lawyers failed to “vigorously argue” that he was acting in self-defense and vacated the manslaughter conviction, setting the stage for a new trial.

O’Neil called the case one of the most challenging in his career. 

Cardilli’s new defense attorney Thomas Hallett, who argued during a two-day hearing in April that his client received ineffective counsel at his trial, called the decision “fabulous.” Hallett was unsure whether the state plans to appeal O’Neil’s decision or proceed directly to a new trial.

“Everyone understands that this is going to be really, really hard for Mr. Muse’s family,” Hallett said. “But everyone is entitled to a fair trial.”


The Office of the Maine Attorney General has not determined its next steps and is currently reviewing its options, spokesperson Danna Hayes said.

“Our office will continue to work to ensure justice for Isahak Muse and his family,” she said.

O’Neil’s ruling deeply disappointed Muse’s family.

“We are devastated and shocked to hear of this decision and can not understand how we could lose my little brother, but Cardilli will get to walk around free,” Muse’s sister Asli Muse said in a statement released by the Office of the Maine Attorney General. “He took my brother’s life, and was convicted of this. It is not fair that he barely served any time and can just walk away from it all. We can’t get my brother back.”

Cardilli will be transferred from the Maine Correctional Center in Windham to the Cumberland County jail, where he will await a bail hearing on Friday afternoon.

Muse, then the boyfriend of Chelsey Cardilli, was a frequent guest in the family’s home, according to testimony from the original trial. Though the Cardilli family originally objected to Muse coming over on the evening of March 15, 2019, they eventually agreed to allow him to stay with Chelsea until 1 a.m.


When Muse refused to leave at that time, Mark Cardilli Jr., then 24, and his father attempted to force him from the home, and a shoving match soon broke out among the three of them and Chelsey Cardilli. Eventually, Mark Cardilli Jr., an Army veteran, ran upstairs to his room and removed a handgun from a safe. He returned, aimed the gun at Muse and told him to leave.

Cardilli testified that Muse instead ran at him and began throwing punches. After backing down the hallway into a corner – one hand protecting his face from blows and another by his side with the gun – Cardilli raised the gun and shot Muse, he said. Forensic experts for both sides agreed that the shots hit Muse in the back at contact range, though they disagreed about whether Muse was turning to run or was twisting away from the gun.

The shooting of Muse, who was Black and Muslim, sparked protests and racial tensions. When Chelsey Cardilli took the stand at trial, she testified that her older brother had told her that Somali people are gang members, that Black people shot by police are always the ones at fault and that Muslims are terrorists.

Though he was sentenced to 7 ½ years in prison, Cardilli’s acquittal on the more serious charge of murder frustrated Muse’s family and supporters.

“Congratulations,” a young man called to Cardilli’s lawyers shortly after Superior Court Justice Nancy Mills’ verdict was read. “You just got a murderer off.”



Despite his decision to order a new trial, O’Neil in his 28-page decision rejected several of the arguments the defense made in its motion for post-conviction review.

He ruled that Cardilli’s original defense attorney, Matt Nichols, was not deficient when he strongly recommended Cardilli elect for a bench trial rather than a jury trial, an unusual move in murder cases. While Hallett argued in April that Nichols colored Cardilli’s judgment and dissuaded him from considering a plea deal by hinting that Nichols’ family had a close relationship with Mills, O’Neil wrote that he trusted Nichols’ testimony that he had not misled his client and that the decision to recommend a bench trial was a valid strategic choice.

He also rejected a second argument that the defense’s misunderstanding of a technical legal standard warranted a new trial.

But O’Neil agreed that Nichols and his co-counsel, Sarah Churchill, who is now a district court judge, had failed to uphold Cardilli’s Sixth Amendment right to effective representation when they chose not to incorporate a specific self-defense statute that justifies the use of deadly force against a person one “reasonably believes” is about to use deadly force against them. He pointed to contradictory testimony at April’s hearing when Nichols was adamant that he did raise the self-defense argument but Churchill said the team instead chose to focus on other self-defense statutes.

“Mr. Cardilli has demonstrated that his attorneys did not have a cohesive trial strategy,” O’Neil wrote in his decision. “The fact that trial counsel were unaware of the disharmony between their two strategies at the time of trial evidences a significant breakdown of communication.”

He noted that the defense’s written closing arguments specifically instructed the court not to evaluate the case based on the fear of deadly force defense.

Nichols did not respond to a message asking about the decision.

It’s unclear if the self-defense argument would have succeeded at trial, said O’Neil, who noted that an appeals court found in 2021 that any fear Cardilli may have had for his life would have been “objectively unreasonable.” But O’Neil wrote that in failing to clearly present the defense, even after Cardilli testified that he feared Muse would knock him out and turn his gun against him, Cardilli’s lawyers could have undermined the credibility of Cardilli’s fear in Mills’ eyes.

Related Headlines

Comments are not available on this story.