BELFAST, Maine — The Jackson man accused of killing a Florida firefighter last February in a drug-related homicide pleaded guilty to manslaughter Wednesday afternoon in Waldo County Superior Court.

In a quiet, monotone voice, Daniel Porter, 25, tried to explain his changed stance to Superior Court Justice Robert Murray. Porter previously had pleaded not guilty to the more serious charge of intentional or knowing murder of 31-year-old Jerry Perdomo of Orange City, Fla. Perdomo was an Iraq war veteran who worked as a firefighter and emergency medical technician for the Seminole County Fire Department. He also had made monthly trips to Bangor for nearly a year to illicitly sell prescription oxycodone, with Porter acting as his Maine middleman, Assistant Attorney General Leane Zainea told the court on Wednesday.

“I guess I’m pleading guilty to this charge to accept my share of the responsibility for letting the situation escalate to this point,” Porter told the court. “Under the circumstances, I believe that I am guilty of this charge.”

But for months, Porter and his attorney, Jeffrey Silverstein of Bangor, have maintained that Porter shot Perdomo in the side of the head with a semiautomatic rifle on Feb. 16, 2012, at a Jackson home after the Florida man had engaged in threatening conduct and communications with him. During both Porter’s first appearance and bail hearing last year, the courthouse was jammed with the Maine man’s family and friends, who strongly indicated that they believe Porter acted in self-defense. Many wore yellow T-shirts that read: “We support the right to protect our families.”

On Wednesday, the courtroom was sparsely filled, with just a half-dozen or so supporters of Porter sitting in the wooden benches. Perdomo’s widow, Tonya Perdomo, also was present. She cried as Zainea gave an overview of the evidence she would have presented if the case had gone to a jury trial, which was scheduled to happen later this month.

Zainea said after the hearing that she was satisfied with Porter’s pleading guilty to manslaughter. Under the plea agreement, the state is recommending Porter be sentenced to 30 years in prison with all but 20 years suspended, and four years of probation. Defense attorney Jeffrey Silverstein is free to argue for a lesser sentence.

If a jury had found Porter guilty of murder, he might have faced a longer sentence — but not necessarily, Zainea said.

“There would have been evidence that would have generated a claim of self-defense, and the state took that into consideration,” she said. “Obviously, Mr. Perdomo can’t tell us what happened because he’s dead. We don’t have another version, other than what the defendant generated.”

Silverstein said after the hearing that Porter ultimately decided that it made sense to avoid a trial.

“A jury might evaluate the circumstances and make a decision that was worse. It was an awfully risky affair,” he said outside the courthouse. “Mr. Porter wanted to spare the anguish, stress and anxiety of a trial.”

Though his family members declined to comment Wednesday afternoon, the defense counsel said that he expects Porter’s supporters to return in force for the sentencing hearing, scheduled for 8:30 a.m. April 22 at Waldo County Superior Court.

“He still has great community respect,” Silverstein said of his client, who has remained in custody in Two Bridges Regional Jail in Wiscasset for more than a year after a judge denied his request for bail. “He’s kept very busy responding to letters from supporters.”

For about an hour in court, Zainea went through the timeline of the events of last February. She said that Tonya Perdomo would have testified about her husband’s decision to drive to Bangor in a rental car, telling his wife that he was going to see a friend for a few days. She asked him if he was going to see Lisa Gould, a Bangor woman Perdomo had been romantically involved with, and he told her he wasn’t.

The last time she heard from her husband was the evening of Feb. 16, when he told her he was on his way to a friend’s house. After that, she heard nothing, Zainea told the court.

Tonya Perdomo eventually looked up the telephone bill and retrieved the last number that Perdomo had called. It was Daniel Porter’s, and she called and texted him 26 times to try to find out where her husband was.

“He texted her back, indicating that Jerry was going up north with Lisa,” Zainea said.

But Tonya Perdomo was worried, and ended up contacting the Bangor Police Department to tell them her husband was missing.

The police investigation ultimately revealed that on the day he was killed, Perdomo packed a gun and two cellphones and told Gould that he had to go collect a debt, according to Maine State Police Detective Brian Strout, who testified at Porter’s bail hearing last March at Waldo County Superior Court.

Porter’s girlfriend, Cheyanne Nowak, met Perdomo at a Route 69 gas station and led him to the rural Jackson home where Porter was staying.

She then left the house to pick up her toddler while the two men were inside playing pool together, Zainea said Wednesday.

Porter later told police that he had owed Perdomo $3,000 and that Perdomo had threatened him and his family. One of the alleged threats was made public during Porter’s bail hearing. At that time, he said Perdomo offered to erase $500 from the debt if Perdomo could rape Nowak on the pool table.

After Porter shot Perdomo, he wrapped the body in blue tarps and borrowed a friend’s truck to move it several miles into the woods near his grandmother’s home on Dahlia Farm Road in Newburgh, Zainea said.

Nearly two weeks later, after a widespread search effort that included local police, wardens and firefighters from Florida, police found the body on a red sled off a woods path.

The day before they found Perdomo’s body, police obtained a search warrant for the Jackson home and found bone fragments and bloodstains. They arrested Porter then, though some statements he made just before his arrest were ruled inadmissible last week by Justice Murray because of Porter’s level of intoxication at the time.

Tonya Perdomo did not want to comment after Wednesday’s hearing, but a victim witness advocate said the widow likely would want to speak after the sentencing hearing.