The South Jersey teenager who pleaded guilty to killing 12-year-old Autumn Pasquale has been sentenced to 17 years in prison, after pleading guilty to a charge of aggravated manslaughter.

Justin Robinson, now 16, pleaded guilty last month to aggravated manslaughter in a deal with prosecutors who were facing some major challenges in the case, including a lack of physical evidence to determine whether he or his brother Dante Robinson killed Autumn Pasquale in October 2012.

Autumn Pasquale Supporters (David Matthau, Townsquare Media NJ)

Robinson, who looked mostly straight ahead during the two-hour sentencing hearing, must serve more than 14 years before he is eligible for parole.

Supporters of the girl's family are not happy with Robinson's sentence.

"We're sending a message out there that our young kids today can kill, go to jail and come out and still have a life," said one man standing outside the Gloucester County Justice Center. "We're getting too soft on crime today- they want to stop crime - get tougher, show em that we're serious."

"I feel as if maybe he'll get his due justice in prison- maybe he'll come out in a box just like she is right now," said another man.

Another man called the sentence a travesty.  "He'll be out when he's in his 30's, and still be able to lead a full life and poor Autumn is dead - it's sickening, I'm sick over it - I'm so tired of these people who think they can go do whatever the hell it is they want to do and they just get a slap on the wrist, it's ridiculous."

Autumn Pasquale Supporters (David Matthau, Townsquare Media NJ)

"There's never going to be justice in a situation like that - but that's just a slap in the face - it's sad, he's going to get his life back and she doesn't, it shouldn't be 17 years, it should be life," said another woman outside the courthouse.

Autumn's grandmother, Mary Pasaquale, hugged supporters after the sentence was handed down and said "Autumn was a gift from God, and a gift to the world and that gift was taken away from us - she's in the loving arms of our savior Jesus Christ, she's in perfect love, she's with my mother and father."

(The Associated Press contributed to this report.)