A 17-year-old boy from Utah shot a teenage girl in the head "because he got annoyed that she messaged him on Snapchat". The victim's mother told a court hearing on Tuesday (10 October) that the bullet was still lodged in her head and she was paralysed on the left side of her body.

During the hearing, Colter Danny Peterson pleaded guilty to first-degree felony aggravated attempted murder of Deserae Turner, 14, on 16 February in the small northern Utah town of Smithfield. He also admitted to a reduced second-degree felony count of robbery, the Daily Mail reported.

Following Peterson's arrest in the case, a juvenile court judge had ordered him and co-defendant Jayzen Decker, 16, to be tried as adults. Decker also faces charges of attempted aggravated murder, aggravated robbery and other crimes.

Judge Angela Fonnesbeck of First District Juvenile Court had said at a trial in May that although Decker was not suspected of shooting Turner, he could have masterminded the plan. "He may not have pulled the trigger himself, but he did take a deliberate and specific action to ensure the crime would be committed," Fonnesbeck was quoted by the Salt Lake Tribune as saying.

The paper added that both the boys accused in the case face a penalty of 15 years to life in the Utah state prison.

The court was told that the two boys hatched the plan to "get rid" of Turner while playing video games.

Peterson 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," Cache County Sheriff Deputy Brian Groves told the court during an earlier trial.

Following the shooting, the boys stole Turner's backpack that had her cellphone and iPod, the court heard.

Turner, who has also lost partial vision, had reportedly told her friends on the day of the crime that she was getting "picked on" by the two boys, who invited her to meet them at a canal to sell her a knife.

The court was also told that the boys' initial plan was to slit Turner's throat and let her bleed to death, but changed the plan to make it a quieter incident.