A Jacksonville teen admitted Tuesday he is guilty of murdering a homeless man, exactly two years after the killing occurred. But it's still unclear why Sharron "Tommy" Townsend, who was 12 at the time, chose to shoot 54-year-old Thomas Zona Trent in the head.

Townsend, who is now 14, shot Trent June 28, 2014, in the parking lot of a shopping center on 103rd Street.

As part of the plea deal reached Tuesday, Townsend pleaded guilty to second-degree murder and the office of State Attorney Angela Corey waived the 25-year minimum mandatory sentence.

Circuit Judge Jack Schemer will have the authority to sentence Townsend to anywhere from 10 to 40 years in prison. His sentencing will occur the week of Aug. 22.

Defense attorney S. Nicole Jamieson said during the hearing she had hoped to get Townsend sentenced as a juvenile, which would have allowed him to avoid adult prison, but Corey personally vetoed that request and insisted he be convicted as an adult.

This is the second juvenile killer Schemer had to deal with in June. He also sentenced Jeremiah Elijah Hill, now 14, to 40 years in prison after he pleaded guilty to the first-degree murder of 25-year-old Tony Vernon Johnson among other charges involved in a gun-deal shooting almost a year ago.

The Jacksonville area has generated national attention due to the number of juveniles charged with murder.

Perhaps the most famous one is Cristian Fernandez, who was facing life in prison without parole when he was charged as an adult with the first-degree murder of his 2-year-old half brother.

Fernandez, now 17, eventually pleaded guilty as a juvenile to manslaughter. He is set to be released on probation when he turns 19 in January 2018.

Edgar Robles, who was 16 when he shot two teenage girls on a school bus, also recently pleaded guilty and was sentenced to 30 years in prison. Robles' sentence includes a 25-year minimum mandatory.

The case of Henry Lee Hayes is still pending. Hayes was 16 when prosecutors and police say he shot and killed 22-month-old Aiden McClendon with the intended target in a yard nearby. Hayes has a pretrial hearing in his case Thursday.

Renata Hannans, a case manager and youth advocate who runs the nonprofit P.S. Never Give Up Hope Inc., met with Townsend weekly since he was arrested. She said she hopes Schemer agrees to put him in a Department of Juvenile Justice facility until he's an adult and doesn't immediately send him to adult prison.

"The state is using his behavior at the jail as a determinant in his sentencing outcome," Hannans said. "An adult jail is not conducive to positive behavior for a child locked in a cage."

At the time of his arrest, police said Townsend probably didn't know Trent, who used a walker and was among the homeless who stuck around the strip of shops and abandoned businesses where he was killed.

Assistant State Attorney Alan Mizrahi told Schemer there was enough evidence to convict Townsend of murder. He is seen on video fleeing the scene and Mizrahi said Townsend told multiple people on Facebook he did it.

Police also had provided surveillance images to the media showing two youths at the scene that early morning, and a 16-year-old friend confirmed for police that it was him and Townsend. Police and prosecutors chose not to charge that teen because he cooperated with police and they did not believe he was an accomplice to the killing.

Schemer asked Mizrahi if Townsend had said why he committed the murder, and the prosecutor said he has never explained his motivation.

The teen told the judge he was pleading guilty because he is guilty but didn't explain why he did it. That explanation will likely come when Townsend is sentenced.

Townsend said he spoke with his lawyer and mother about his decision to accept the plea deal. When Schemer asked whether his mother agreed, a voice from the back of the courtroom could be heard saying "hell no."

Bailiffs chastised her and another woman for the outburst. Afterward the woman who appeared to be Townsend's mother went into the courtroom hallway and burst into tears. Both women declined to talk with the Times-Union.

Hannans said she hoped people understood Townsend is a child.

"His behavior is that of a child," she said. "He acts like a child, he thinks like a child, he has hopes and dreams like a child."

Hannans said she also worries that Townsend doesn't really understand the concept of time or grasp what being locked up for 40 years might mean.

"The only thing you see in the media is a child in a jumpsuit or jail suit with a headline that says 'child murderer,' " Hannans said. "But he is a child I've seen humanity in."

He has experienced hardships and feels for other people and has empathy for the feelings and sufferings of others, Hannans said.

Townsend will benefit from recent U.S. Supreme Court rulings that found it was unconstitutional to mandate juveniles get life in prison without a chance of parole. If he gets more than 25 years in prison, a judge will review his sentence at the 25-year mark to consider whether Townsend should get out.

Larry Hannan: (904) 359-4470