(CNN) — The prosecution and defense rested their cases Wednesday in the manslaughter trial of James Crumbley, the father of the teenager who fatally shot four students at his Michigan high school in 2021, in a case that comes a month after the shooter’s mother, Jennifer, was convicted of the same charges.

Prosecutors recalled one witness on Wednesday morning for brief testimony before resting.

The defense then called one witness, James Crumbley’s sister Karen, before they rested. She testified that she had spent several days with the Crumbley family in April and June 2021 and did not notice anything concerning.

With the jury out of the room, James Crumbley said he will not testify. “It is my decision to remain silent,” he said.

Closing arguments are expected later Wednesday.

The trial comes more than two years after Ethan Crumbley used a SIG Sauer 9mm weapon, which his father bought for him on Black Friday, to kill four students and wound six students and a teacher at Oxford High School on November 30, 2021.

Prosecutors have argued James Crumbley acted with “gross negligence,” saying he did not properly secure the firearm and ignored warning signs of his son’s spiraling mental health.

“That nightmare was preventable and it was foreseeable,” Oakland County Assistant Prosecuting Attorney Marc Keast said.

Defense attorney Mariell Lehman has pleaded ignorance on her client’s behalf, saying Crumbley did not know his son had gained access to the weapon and did not believe there was an imminent, immediate threat of danger.

“You will not hear that James Crumbley knew what his son was going to do,” she said in opening statements. “You will not hear that James Crumbley even suspected that his son was a danger.”

James Crumbley has pleaded not guilty to four counts of involuntary manslaughter and faces up to 15 years in prison if convicted. His wife, Jennifer Crumbley, was convicted of the same charges last month in a case highlighted by her own testimony in which she pushed blame onto others and expressed no regrets.

The case against him has been altogether similar to the one against his wife, featuring testimony from shooting survivors, police investigators and school employees. However, there have been some key differences, as prosecutors have focused more on James’ decision to purchase a firearm for his son and how he stored it, while featuring less evidence about his personal life or interests.

Ethan was sentenced last year to life in prison without parole after pleading guilty to terrorism causing death, four counts of murder and 19 other related charges. He did not testify in his mother’s trial, as his attorneys had said he would invoke his Fifth Amendment right to silence if called.

The cases against the parents are set to test the limits of who is responsible for a mass shooting. Prosecutors aiming to expand the scope of blame in mass shootings have used an unusual and novel legal strategy by arguing the shooter’s parents are responsible for the deaths because they got him a gun and disregarded signs of his mental health issues.

Parents have previously faced liability for their child’s actions, such as with neglect or firearms charges. Yet Jennifer Crumbley’s case was the first time a parent of a school shooter was held directly responsible for the killings.

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