A Muddy Creek Township man convicted earlier this year of third-degree murder in the 2014 shooting death of his friend will spend 18 to 40 years behind bars.

The sentence handed down to Jeremey Sickenberger, 25, came after a nearly two-hour long sentencing hearing that saw defense attorney Marco Attisano call numerous witnesses, including a doctor that diagnosed Sickenberger as being on the “high functioning” end of the autism spectrum.

Attaisano and the doctor, Allen Clark, argued that the diagnosis confirmed years of suspicion by Sickenberger's mother and merited consideration during sentencing.

Sickenberger's apparent lack of emotion and remorse regarding the shooting death of Thomas “T.J.” Stockman, 21, of Portersville on April 17, 2014, was hotly-debated during a four-day trial that concluded with a jury finding him guilty of third degree murder. It's also been the subject of litigation during the run-up to sentencing, with prosecutors arguing that Sickenberger's conduct merited the harshest sentence guidelines allow: 40 years in prison.

Sickenberger read multiple statements to the court on Thursday, saying repeatedly that he knew his sorrow and remorse would not bring Stockman back, but that he hoped he would one day be forgiven by the man's family and friends for actions he acknowledged were “reckless” and amounted to “a terrible mistake.”

“I know my actions caused his death. For that, I am sorry,” Sickenberger said. “I still feel guilt and pain for what I've done.”

It was Stockman's mother, Natalie, who showed raw emotion before Judge Timothy Shaffer. She read a statement describing her son as a loving and generous person whose life plans were derailed by a callous Sickenberger, who “shot him and left him there dying,” without help, and has since “not shown any remorse for taking TJ's life. Not once.”

Police have said that Sickenberger, Stockman and several other people had gathered on the evening of the shooting at Sickenberger's home on Robbie Way when Sickenberger shot Stockman in the side of his chest with a .22-caliber rifle.

During trial state police investigators testified that they received conflicting statements from those present about what transpired in the immediate aftermath of the shooting, as well as unusual behavior from Sickenberger himself.

Stockman, in her statement to the court on Thursday, said that the numerous delays in sentencing proceedings, which were initially scheduled for October, have been “a cruel torture for my family.” She said her grief has been sharp and “a constant roller coaster of emotions every single day,” and asked the court for closure.”

“There is truly no greater heartache than burying your child,” Stockman said.