(CNN) -- A jury in Kentucky Friday night acquitted 17-year-old Joshua Young in the beating death of his stepbrother, Trey Zwicker, two years ago.
Young also was found not guilty of tampering with evidence.
Josh Gouker, Young's father, pleaded guilty to murder in Zwicker's death, and was sentenced on July 26 to life in prison. But prosecutors said Young worked with Gouker to beat Zwicker as the teen suffocated in the mud of a ditch behind a Kentucky high school.
"Trey Zwicker was brutally murdered at age 14 ... because Josh Gouker is a control freak and because Josh Young wanted to impress him," prosecutor Elizabeth Brown told the jury in Jefferson County Circuit Court during Friday's closing arguments. She said Gouker was upset with Zwicker's mother after she aborted Gouker's unborn child, and he wanted revenge.
Jurors could have found Young guilty of murder whether they believed he acted alone or with someone else. The tampering with evidence charge accused Young of throwing away clothes and a bloody bat after the murder.
Before deliberations began, Brown told jurors not to feel sorry for the defendant because he's young or because he had a bad father or a bad life.
"You cannot let sympathy add reasonable doubt," Brown said. "He was not coerced into doing this. He bragged about it, laughed about it."
Leslie Smith, delivering the closing argument Friday for the defense, turned the spotlight on Gouker. She called him a "jerk" without a conscience and described him as a master manipulator who killed Zwicker alone.
"Do you really think he involved anybody else at all to carry out this horrible crime," Smith said.
Smith also told jurors that the only reason investigators looked at Young is because of Gouker, who "duped the police and then he duped them again and then he duped everybody. He's good at it, he's just good at it."
Smith closed her argument by questioning why Young is even on trial.
"Why are we here? Send this kid home -- wherever that's going to be. Just send him home," she said.
Young wiped his eyes and his nose as he exited the courtroom during a short break between the attorneys' closing arguments.
The jury in Louisville deliberated for about eight hours before returning its verdicts.
InSession's Jackie Damico contributed to this report.