AUGUSTA — A Kennebec County jury on Wednesday found William Lord not guilty of throwing his infant son down a flight of stairs.

The jury of seven women and five men deliberated a little more than two hours before clearing the 40-year-old Lord of charges of aggravated assault and domestic violence assault on a child less than 6 years old – his 3-month-old son, Preston – on Oct. 19, 2014, inside Lord’s Wayne home.

Lord, his once wavy hair now neatly cropped, dressed in a black sport coat and green slacks, had no visible response to the verdict as he faced the front of the courtroom, away from spectators. The verdict brought tears of apparent relief from three women with whom Lord had waited during deliberations.

The verdict came at the end of a trial that began Tuesday morning and went to the jury around 2 p.m. Wednesday, after closing arguments.

Assistant District Attorney Kristin Murray-James began her closing argument in the same way she opened the trial, by holding up a picture of Preston Lord.

“Yesterday morning I told you this case would be about this little fella,” Murray-James said.

She said William Lord intentionally threw his son, who was resting unsecured in a car seat, down a set of 10 wooden stairs during an argument with the baby’s mother, Ericka Melanson, about a text she had sent to another person. Murray-James said Lord held the car seat and baby over his head at the top of the stairs before throwing both down the stairs.

“She told you how she saw him at the bottom of the stairs. That’s where she saw him, unmoving, underneath the blanket,” Murray-James said, recalling Melanson’s testimony on Tuesday. “You heard Ericka tell you she ran down those stairs and that she felt the defendant’s foot thumping on her back and he said he was going to push her down, too.”

Murray-James said others in the house the night Lord’s son was injured testified about hearing a commotion and a crash, but Lord’s attorney, Robert Ruffner, said during his closing argument that the case against Lord was based on Melanson’s version of events.

“This is the state’s case,” Ruffner said, holding his hands over his head as if he were holding something aloft. “This is what Ericka said happened. Supposedly William took the car seat and chucked it down the staircase. They premise everything, and their view of everything, on this being true beyond a reasonable doubt.”

Ruffner said the physical evidence contradicted Melanson’s testimony. A child thrown down a flight of stairs, he said, would suffer more significant injuries.

“The physical evidence shows he was fine, other than the skull fracture,” Ruffner said. “Other than mild scalp swelling he didn’t have any other injuries.”

Following the incident, Melanson borrowed Lord’s car to drive the baby to MaineGeneral Medical Center in Augusta, where a physician found a swollen spot on the back of the boy’s head. Further tests revealed he had a fractured skull.

Murray-James said Lord never checked on his son’s condition before going to the hospital or at any point afterward. His long text to Melanson, Murray-James said, was to inquire when she would return his car.

Melanson, Preston and an older daughter, were living with Lord inside the Wayne home he shared with his fiancee, and the couple’s two children. Murray-James said Lord was angry that Melanson was pushing him for a relationship.

“She pushed him. She made him mad,” Murray-James said. “He broke. Drunk and angry, he snapped. He lost it. He stood at the top of these stairs and he threw … Preston Lord down those stairs, fracturing his skull.”

Before the incident, Lord had been fired from his job as a registered nurse at Riverview Psychiatric Center. The firing followed a review of a December 2013 incident in which Lord approved the use of pepper spray by a state corrections officer on forensic patient Arlene M. Edson. The woman was left for hours in restraints with the irritant on her skin despite being compliant and not threatening the staff, according to a report.

Lord is no longer working as a nurse. He agreed to have his nursing license placed on inactive status in an August 2015 consent agreement with the state Board of Nursing.

At the hospital, physicians carefully checked Preston Lord for other injuries, including internal damage, but found only the fractured skull, Ruffner said. The child was alert and even smiled at the doctor who was helping him.

“If he was actually thrown that way and ejected he would have other injuries. He didn’t,” Ruffner said. “There wasn’t a scrape. There wasn’t a cut. Besides the swelling there were no other bruises.”

Ruffner argued that any mother who witnessed her infant old child be thrown down the stairs would have called for an ambulance or at least called the hospital on the way to alert them of her arrival. Melanson did neither, Ruffner said.

“Preston left, not in a life threatening manner, he left with his mother,” Ruffner said. “And William didn’t know she was going to the hospital.”

Ruffner said Melanson, in June of 2012 while pregnant with her daughter, claimed she was thrown out of second story window. Later, Ruffner said, Melanson said she made up the story because she was mad at the boyfriend. Melanson on Tuesday said she “lied about lying” and that she had in fact been thrown out the window, Ruffner said.

He suggested that Melanson had also made up a story to hurt Lord.

“She is mad at him,” Ruffner said. “She wanted to have a relationship with him. It wasn’t going to happen.”

Ruffner said the jury had to decide whether or not they could believe Melanson beyond a reasonable doubt.

“Her story is incredible in the truest definition of the word,” Ruffner said. “It is beyond belief.”