CHARDON, Ohio – An unremorseful Ohio teenager who opened fire on his classmates in 2012 is appealing his life sentence on the basis that he was 17 at the time, and shouldn’t have been tried as an adult.

T.J. Lane pleaded guilty to killing three students in the cafeteria of Chardon High School east of Cleveland in February 2012, and was sentenced to life without parole at a hearing in which he taunted his victims’ families, the Associated Press reports.

“The hearing took place inside a courtroom where a smirking Lake wore a T-shirt with ‘killer’ scrawled across it and gestured obscenely toward the victims’ families during his sentencing,” the new service reports.

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Lane’s attorney, Michael Partlow, is challenging the case’s transfer from juvenile court to adult court after the Ohio Supreme Court agreed to hear an unrelated case involving a 16-year-old who was sentenced to prison. Ohio law requires 16- and 17-year-olds to be tried as adults when the alleged offense is severe, according to the AP.

“What is the difference between a 15-year-old and a 17-year-old? He is still not an adult,” Partlow argued in a plea for Lane’s resentencing.

Partlow cited a recent state Supreme Court case in which the life-without-parole sentence of 17-year-old Eric Long was overturned. Long was convicted with two adults of two killings near Cincinnati, according to the news service.

“The high court ruled that youth must be considered as a mitigating factor and the record must reflect that the court did so. The ruling said a trial court must reconsider Long’s sentence, though it doesn’t block him from being sentenced again to life without parole,” the AP reports.

Partlow argues the judge in Lane’s case didn’t formally address his client’s age, but Geauga County Prosecutor James Flaiz contends age was a consideration.

Flaiz also argued that several rulings have upheld the state law that transfers 16- and 17-year-olds to adult court for serious offenses and the law was intended to prevent the teens from getting away with murder. Without the law, a 17-year-old could conceivably kill someone and be set free at 21 years old under the juvenile court system.

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Lane, now 19, was not present at the hearing this week. It could be months before an appeals court decides on the issue, the AP reports.