JACKSON, Mich. -- A southern Michigan man convicted of killing his ex-girlfriend's 18-month-old son has been sentenced to life in prison without parole.

Scott Jurewicz was found guilty in November of first-degree murder and first-degree child abuse in the March 2015 death of Brenden Hartranft. He apologized on Thursday in court before being given the mandatory punishment in the case.

The Jackson Citizen Patriot reports Jackson County Circuit Court Judge Thomas Wilson told Jurewicz "I think you're a psychopath" before sentencing him.

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"You affected so many lives," Circuit Judge Thomas Wilson said, reports MLive. "Seeing your complete lack of conscience, I don't think you'll do well in prison."

Scott Jurewicz WLNS-TV

Jurewicz has admitted he gave the child a shake and put him down hard in a play pen in the home the couple shared in Michigan Center, near Jackson. The 29-year-old admitted in police interviews to shaking the boy because he wouldn't stop crying, reports CBS affiliate WLNS-TV.

An autopsy reportedly determined the child died of abusive head and neck injuries.

"You didn't just kill a child, you destroyed everyone's life," the child's grandmother Dawn Wilson said in court to Jurewicz, reports MLive. "I hope you can never forget his name. You have blood on your hands. I wish I could put a photo of Brenden in your cell so you would never forget what you did to him."

Defense lawyer Eric White says Jurewicz continues to maintain his innocence and will be appealing his conviction.

While Jurewicz was being investigated in Brenden's death, he began a relationship with another woman, Andrea Conaway, whose 21-month-old son Jesse Pepper Jr. was found dead in his Pack N' Play in May 2015, MLive reports. He had reportedly been smothered and suffered blunt force trauma to his head.

Jurewicz has not been formally implicated in that case, but prosecutors presented evidence about both boys' deaths at his trial, MLive reports. Conway, who invoked her Fifth Amendment protection and didn't testify during Jurewicz's trial, hasn't been charged but is reportedly considered a suspect.