Trevor Averill of Buckfield embraces Michelle Levesque, the mother of their daughter Harper Grace Averill, the 2-month-old who died in a shaking incident in 2020. Averill was convicted in January of manslaughter in Harper’s death, and was sentenced Friday in Androscoggin County Superior Court in Auburn to 23 years in prison with all but 18 years suspended. He is appealing the sentence. Sun Journal/Joe Charpentier

AUBURN — A Buckfield man sentenced Friday for the manslaughter of his 2-month-old daughter in 2021 has appealed his 18-year prison sentence.

Androscoggin County Superior Court Justice Jennifer Archer sentenced Trevor Averill, 31, to 23 years in prison on Friday. Averill was ordered to serve 18 years of that sentence with six years of probation following his release.

He is currently serving his sentence at Maine State Prison in Warren.

The trial, which began Jan. 21, featured testimony from medical experts saying infant Harper Grace Averill died from “non-accidental trauma” caused by severe shaking. Prosecutors argued that her father was responsible for her violent death.

Averill’s attorneys James Howaniec and Verne Paradie countered that insufficient evidence linked him to the fatal injuries and that the injuries instead could have resulted from a previous dropping incident weeks before the 911 call on July 21, 2020, when Harper stopped breathing.

Howaniec and Paradie filed appeal documents Sunday evening outlining their reasoning for appealing the “intemperate, arbitrary, and capricious” sentence, according to their filing.

“The court penalized Trevor for ‘not taking responsibility’ for his daughter’s death, (which is) in gross violation of his due process rights to the presumption of innocence and right to remain silent,” Howaniec wrote in the appeal. “Trevor has maintained his innocence from the beginning and is steadfastly supported by his attorneys in this regard.”

Averill’s defense challenges the use of “shaken baby syndrome” as a basis for conviction, saying it is a controversial diagnosis without evidence of a violent action. During the trial, attorneys presented several expert witnesses who testified that a dropping incident from a month prior would have produced the skull fracture found during Harper Averill’s autopsy as well as other symptoms.

In the appeal documents, Averill’s attorneys argued that his 18-year sentence is harsher than other manslaughter cases and questioned why Archer imposed a sentence far exceeding the 10-year plea deal prosecutors offered before trial. They also said Archer disregarded comparable sentences from the past 20 years without explanation.

Averill’s appeal, if accepted, could involve further legal proceedings concluding with a reduction in his sentence. Until then, Averill remains in Maine State Prison.