WISCASSET – A Wiscasset man accused of shaking a toddler so violently that she later died from her injuries pleaded guilty Monday under an agreement with prosecutors.

Erik Hart pleaded guilty to manslaughter in Lincoln County Superior Court in exchange for the state dropping a murder charge. The agreement also called for a sentence cap of 10 years in prison.

Hart was accused of shaking his 1-year-old stepdaughter and slamming her head against the floor two days before she died in June 1998.

An autopsy showed Chelsea Taplin suffered more than 20 serious injuries, including broken bones. She also had marks around her neck.

Prosecutors say Hart threw Chelsea to the floor when she wouldn’t stop crying in June 1998. They also say his wife, Stacie Hart, failed to provide health care and a safe living environment.

With his guilty plea, Erik Hart accepted responsibility for delivering the fatal blows to the girl.

The plea agreement called for a maximum sentence of 15 years with five years suspended. That limits the maximum amount of time Hart could be ordered to serve in prison to 10 years.

Whether the plea agreement would be accepted by Justice Nancy Mills remained unclear on Monday.

Mills planned to decide whether to sign off on the plea agreement after hearing testimony from witnesses about the abuse suffered by Chelsea before she died.

Assistant Attorney General Lisa Marchese planned to call eight witnesses, beginning Monday. Testimony was expected to continue through midweek.

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