Robert William Boettger, 28, of Cambridge, made a court appearance on second degree murder charges in connection with the death of four-year-old Rayna Gagne.
Boettger remains in custody following the appearance on Wednesday, the first he has made in person since second degree murder charges were laid.
He reportedly showed no emotion, but acknowledged several people in the courtroom.
Boettger was initially charged with aggravated assault in the case, but charges were upgraded shortly after Gagne died of her injuries.
On Thursday, Feb. 3, emergency services were called to the Cambridge townhouse of Gagne's mother, Jenn Taylor, for a report of an unconscious child.
Gagne was found with severe head injuries and died in hospital two days later.
Boettger, who was Taylor's live-in boyfriend, had been babysitting Gagne while her mother was at work. Taylor returned home to find paramedics working on her daughter.
Taylor has described the four-year-old as an amazing girl who loved being a princess, playing with her Barbies, colouring and drawing.
Boettger will return to court via video link on March 1.
The defence lawyer, crown attorney and defendant's brother all declined to comment on the upgraded charge.
