A teenager who was convicted of killing three classmates at an Ohio high school last year showed up at his sentencing on Tuesday wearing a T-shirt with the word "killer," and then flipped his middle finger at the families of the victims.

According to ABC News, TJ Lane removed a blue button down shirt after arriving to court to reveal a white T-shirt with the word "killer" handwritten across the front in black letters.

Lane then used his opportunity to make a statement to the court to hold up his middle finger to the families of those he was convicted of killing. Lane made a statement that Cleveland's The Plain Dealer described as "unintelligible," and then concluded by saying, "Fuck all of you."

"Frankly, I wasn't prepared for this," the prosecutor remarked. "This is confirming what we have known all along, that this was a cold, calculated, premeditated killing."

CNN reported that Lane had "smiled" at the notion that juvenile killers could not receive the death penalty.

In the end, Geauga County Common Pleas Judge David Fuhry sentenced Lane to life in prison for the 2012 murders of 16-year-old Daniel Parmertor, 16-year-old Demetrius Hewlin and 17-year-old Russell King Jr. Lane also shot three other students. One of those teens is now confined to a wheelchair.

It was not immediately clear why Lane was allowed to wear the "killer" T-shirt in open court.

[Editor's note: The Supreme Court ruled in 2005 that the death penalty was unconstitutional for those who had committed crimes while under the age of 18.]

Watch this video from USA Today, broadcast March 19, 2013.

Watch this video from CNN, broadcast March 19, 2013.

[Correction: This post originally said juveniles could receive the death penalty.]