POMPANO BEACH (CBSMiami) – The trial of a Pompano Beach teen accused of nearly killing a 15-year-old girl when he stomped on her head with steel-toe boots got underway Tuesday with jury selection.

Wayne Treacy, 17, has pleaded not guilty to the attack and his attorney, Russell Williams, has said he plans to use insanity as a defense.

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Treacy allegedly attacked Josie Lou Ratley on March 17th, 2010 at the bus stop in front of Deerfield Beach Middle School after a heated exchange of text messages. Both were 15-years old at the time.

Treacy has reportedly admitted that he rode a bike to the school to confront Ratley after receiving a text message from her phone telling him to “go visit” his dead brother referring to his older brother’s body, which was found hanging from a tree in front of a church five months earlier.

Treacy saw the body before it was taken down, according to his lawyer and suffered post traumatic stress disorder but never got treatment.

Treacy reportedly told psychologist Michael Brannon when he received the text message, “an explosion went off inside” and he put on his brother’s clothes and steel-toe boots, which he used to kick Ratley in the head. Ratley suffered irreversible brain damage from the attack and has no memory of the incident or the text message exchange that instigated it.

His attorney Russell Williams told CBS4 News that Treacy is “nervous but anxious to get the trial over with.  Williams said Treacy asked him on Friday, “if it’s alright if he throws up so I hope his mental condition doesn’t interfere with the trial.”

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Williams said he intends to prove to a jury that Treacy suffered from Post Traumatic Stress Disorder related to the suicide of Treacy’s older brother five months before he snapped.

He said Treacy needs mental health treatment not prison time.

“He didn’t know what he did was wrong,” said Williams.

Treacy has been held without bond in the juvenile section of the Broward Main jail since he was arrested.

Treacy has been charged as an adult for 1st degree attempted murder which could give him up to 50 years jail time.

Once the jury is picked, the trial is expected to begin July 9th.

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Also charged as a juvenile in the attack was Kayla Manson, 14 at the time, who allegedly helped Treacy find Ratley when he arrived at the school. Manson has said she didn’t know what Treacy was planning to do and was charged as an accessory to the crime.