Michigan school shooter's father allegedly threatened to destroy the prosecutor in the case against him

The prosecutor who brought a historic conviction against the father of the Oxford High School shooter says he directly threatened her in jailhouse phone calls.

The Oakland County prosecutor's office said in a statement Wednesday that James Crumbley, 47, made threats that addressed prosecutor Karen McDonald by name about would happen to her after his release from jail.

"Those threats are serious, and they also reflect a lack of remorse and a continued refusal to take accountability for his part in the deaths of Hana, Madisyn, Tate and Justin," the Oakland County prosecutor's office said in its statement.

A Michigan jury last week found Crumbley guilty on four counts of involuntary manslaughter for the shooting his son carried out, killing four classmates in a Detroit suburb.

Crumbley's defense attorney, Mariell Lehman, declined to comment Wednesday in response to the prosecutor's statement.

Crumbley and his wife, Jennifer Crumbley, who was convicted on the same charges at a separate trial in February, are the first parents in America to be charged for a school shooting committed by their child.

The Oakland County sheriff's office said on March 7, after the first day of testimony in his trial, that James Crumbley made "threatening statements" from jail, but did not provide details about the threats then.

The judge signed an order earlier that day after the prosecution and defense attorneys reached an agreement to restrict his jail communications. For the rest of the trial, Crumbley could talk only to his lawyer and legitimate clergy and do research to help his defense.

“There’s a disagreement about what was said and the nature of that stuff,” Lehman said Monday, before details about the nature of the threats became public.

She declined to expand on her characterization of Crumbley’s conversations and added that lawyers on each side agreed at trial to try to keep it out of the media.

Both parents are set to be sentenced April 9. The prosecutor's office now says the Oakland County Sheriff's office is investigating the threats, which will be included in a sentencing memorandum the prosecutors plan to file.

Sources close to the Oakland County prosecutor's office confirmed to NBC news earlier in the week that Crumbley allegedly told his sister over the course of multiple jailhouse phone calls that he was going to make it his goal in life to destroy McDonald.

He said he wanted to ruin her, that she was going to hell soon, that she better be scared and that she was done, according to the sources.

Those details of the threats were first reported Monday by the Detroit Free Press.

Asked about the threats on March 15, McDonald said that “he made a lot of threats” but that she didn’t want to elaborate because she didn’t want to give him more attention.

“I just don’t think it’s important to talk about," McDonald said then.

The Crumbleys' son killed four students — Madisyn Baldwin, 17; Tate Myre, 16; Hana St. Juliana, 14; and Justin Shilling, 17 — and wounded seven other people when he opened fire with a handgun Nov. 30, 2021.

Crumbley had bought the Sig Sauer 9 mm handgun days before the shooter used it, and prosecutors say it wasn’t kept secured. McDonald last week called the facts "egregious" and said that the shooting was foreseeable and that the parents could have prevented it "with just the smallest of efforts."

At trial, school staff members testified that both the parents were called to the school the day of the shooting about a drawing their son had made depicting a gun and a person who had been shot. Neither of them told staff members he had access to a weapon, and they said they couldn’t take him home, citing work.

Crumbley's defense maintains he had no way of predicting that his son would start shooting hours later.

"He wished that he had taken his son home that day. If he had known what was going to happen, he would have made different decisions," Lehman said Monday, adding that Crumbley feels terrible about what happened to the families.

The sentencing hearing will be the firs t time the Crumbley parents — who can’t communicate with each other from jail — could potentially see each other since they attended joint hearings before their trials were separated. They each face a maximum of 15 years in prison for the involuntary manslaughter charges.

This article was originally published on NBCNews.com