WISCASSET – The man who admitted shaking his 13-month-old stepdaughter to death made a tearful apology in court as a judge weighed whether to accept a plea bargain.

Erik Hart, 29, admitted Thursday to using what he described as a “gross amount of force” when he pulled Chelsea Taplin off the couch and threw her onto the floor because she wouldn’t stop crying in June 1998.

The girl died two days later at a Portland hospital. An autopsy showed she suffered more than 20 serious injuries, including broken bones.

“I can’t ask them to forgive me,” Hart said, referring to members of the Taplin family who attended the hearing in Lincoln County Superior Court. “I’m having a hard time forgiving myself. All I can ask is that you’ll get some closure on this, and you’ll be able to move on.”

With that, he sat down and buried his face in his arms.

Hart pleaded guilty Monday to manslaughter in exchange for the state dropping a murder charge. The agreement, which the judge can accept or reject, calls for a maximum sentence of 10 years in prison.

Hart’s testimony capped a four-day sentencing hearing during which prosecutors tried to paint him as a longtime abuser capable of causing the toddler’s injuries. His defense lawyers, meanwhile, suggested that many of the injuries were caused by the girl’s mother, Stacie Hart.

In his first public comments since his arrest more than two years ago, Erik Hart told the court he cries at nights thinking about all the things that Chelsea, and he, will miss out on.

“Teaching her to ride a bike, teaching her to dance, staying up late waiting for her to come home, even walking her down the aisle,” he said.

The day Chelsea was injured, he was watching a movie with Chelsea’s 5-year-old sister, Brianna, when the baby’s crying angered him.

“Without thinking, I pulled her off the couch with so much force her head snapped back,” he said. “I put her on the floor with … a gross amount of force. If any other parent had been watching, they would have realized it wasn’t reasonable.”

Hart’s lawyer, Michael Turndorf, told the judge his client’s chances of rehabilitation are high.

“He’s learning his lesson,” he said. “He’s been a model prisoner. He’s a young guy with a future. He lost control.”

Turndorf pointed to Stacie Hart as the reason Chelsea’s injuries began.

“She couldn’t stand one second of time with those kids,” he said. “That’s the reason the injuries started to occur.”

Stacie Hart testified Wednesday that she was a terrible mother, but she didn’t take responsibility for the child’s injuries, nor did she accuse her husband. She said she mentally abused her children, and said she noticed more bruises, scratches and bumps on Chelsea after Hart moved into their house.

She has pleaded guilty to assaulting and endangering the welfare of her daughter for her role. Both she and Erik Hart are expected to be sentenced in January in Superior Court.

Justice Nancy Mills is expected to use the testimony to determine how long Erik Hart will spend in jail.

Assistant Attorney General Lisa Marchese is recommending the maximum allowed under the agreement: 15 years in prison with all but 10 years suspended, followed by six years of probation. Hart’s lawyers are arguing for a shorter sentence.