JACKSON, MI - A father who confessed mid-trial to brutally beating his two sons will spend the next several decades behind bars.

Circuit Judge John McBain sentenced James Harbert, 50, to serve 20 to 40 years in prison on Wednesday, Oct. 25.

"You destroyed our family," Harbert's 15-year-old son, who is a victim of his abuse, wrote in a statement that was read aloud to the court. "People say you (James Harbert) were a nice guy. I wish I knew that guy. When I see you in my nightmares, I will no longer be afraid, because you are a weak and sad man."

Harbert pleaded guilty as charged to three counts of first-degree child abuse during the first day of his criminal trial, Sept. 12, shortly after his son took the stand to tell the jury about the abuse he suffered at the hands of his parents.

"We failed our sons," Harbert said in court on Wednesday, lowering his head as he spoke. "We expected too much from them, disciplined them too harshly and put the dogs first to maintain our lifestyle. I'm proud of my kids and I miss them."

The children's mother, Tina Harbert, was scheduled to be sentenced alongside Harbert but, due to a clerical error in her pre-sentence report, had her case adjourned and rescheduled for Wednesday, Nov. 1.

"I have never seen a case of child abuse this bad," McBain said in rendering his sentence. "When I saw the injuries, I saw this was not a case of a single beating that got out of control, it was systematic. They were beaten so badly they had to put on diapers to cover their oozing wounds."

The Harberts' daughter spoke on her father's behalf during the sentencing, stating she has always had a great relationship with him and that a lot of the things brought up during trial were not true.

"My dad is my rock," she said. "He was always there for the boys when they were crying or upset. Things were not all bad."

Harbert was charged after grandparents discovered signs of severe physical abuse on their then 12-year-old grandson while he was in their care on Sept. 20, 2015. The boy's 10-year-old brother also showed signs of abuse.

In December 2015, the Jackson County Prosecutor's Office issued two counts of second-degree child abuse against Tina Harbert "for failure to protect" both sons from "serious physical harm and serious mental harm" allegedly inflicted by her then husband.

Her charges were upgraded to first-degree child abuse after her case was sent back down for another preliminary examination before District Court Judge Joseph Filip, June 20, 2016.

After two hours of deliberations, a jury of seven men and five women found Tina Harbert guilty Sept. 15.

James Harbert was credited for 707 days served.