One of the two Utah teens convicted of attacking a 14-year-old girl because her social media messages were annoying has been sentenced for at least 15 years.

Jayzon Decker, 17, who helped his friend Colter Peterson in planning the attack against Deserae Turner while playing a video game, was handed the jail term on Wednesday (7 February) while the girl bravely faced him in the court. Both the boys planned the attack to "get rid" of Turner, who was messaging Peterson on Snapchat.

Peterson had told Decker that Turner was texting and Snapchatting him too frequently, following which Decker responded: "It would be pretty easy to get rid of her", the court documents revealed.

The pair lured the victim to a deserted dry canal bed behind a high school in Smithfield on 16 February and then shot her in the head. But fortunately, the girl survived.

However, the attack has left Turner partially blind and the bullet is still lodged in her brain leaving her struggling to walk, dress herself and function through unbearable headaches.

Following the shooting, Decker also picked up the spent shell casing "as a memento", which was later found displayed on his bedroom windowsill by investigators, The Daily Mail reported.

Peterson was given the same jail term last week. Before Decker's sentencing, his lawyer Shannon Demler sought a shorter minimum sentence, saying his role was less serious as he was not the one who pulled the trigger. But First District Judge Brian Cannell turned down the plea and said the boy was as legally and morally responsible as his friend, Peterson.

"I tried to read you today. I tried to see if you were past feeling. I don't know what's scarier - the actual act, or not understanding it, or the lack of emotion," Cannell said.

Decker was tried as an adult after he pleaded guilty to attempted aggravated murder and felony obstruction of justice.

Meanwhile, it was reported that like last week when Peterson was sentenced, this week also Turner was present in the court for the sentencing hearing and bravely confronted her culprit.

"No amount of [prison] time will fix you. You are evil. ... You kept the shell for a trophy. How sick is that? Good luck in prison and remember that, because of you, my life is a prison, too," the teen girl told Decker, The Salt Lake Tribune quoted her as saying.

She asked Decker: "What do you have against me? You don't even know me. I hate what you did to me. ... I hate that I don't have a regular teenager life anymore. I hate that I won't ever have a regular life."