One Florida juror said it came down to the question of whether it was a "cold-blooded" killing or a "hot-blooded" killing.

In the end, the jury Wednesday found 14-year-old Nathaniel Brazill guilty of second degree murder in the fatal shooting of his English teacher last year.

Juror Toni Sellier said the panel focused on the final seconds before the shooting, and not on the boy's age or testimony. Brazill, who was 13 years old at the time of the shooting, testified on the stand that he did not intend to kill popular teacher Barry Grunow and that he accidently pulled the trigger.

Sellier said the jury determined Brazill, already upset about being suspended, snapped when his teacher told him he couldn't see two girls in his class.

The jury rejected a more serious charge of first-degree murder that could have put the boy in prison for life.

Brazill was also found guilty of aggravated assault with a firearm.

He could receive 25 years to life in prison when sentenced on June 29.

The jury of nine women and three men deliberated for more than 14 hours before returning the verdict.

The teen, a well-regarded wise-cracking student without any previous criminal record, shot 35-year-old Grunow once between the eyes in the doorway of the teacher's Lake Worth Middle School classroom last May.

It was about two hours after he was sent home early for throwing a water balloon. The shooting happened minutes before the start of summer vacation.

Brazill, wearing a shirt and tie and seated between his lawyers, showed no emotion as the verdict was read.

He testified in a monotone voice last week that the gun went off unintentionally. He showed emotion only once, crying after the prosecutor asked him on cross-examination what happened to Grunow after the shooting.

The case was the latest involving teen violence in Florida. In March, a jury sentenced 14-year-old Lionel Tate to life in prison without possibility of parole for the 1999 murder of a 6-year-old family friend.

Jurors heard emotional testimony from about a dozen middle-school students who either saw their classmate shoot Grunow or point the silver .25-caliber semiautomatic pistol at math teacher John James as he fled.

On a school surveillance video of the shooting shown to jurors, Brazill extended his arms and pointed the gun at Grunow for four seconds before firing.

Prosecutors were seeking a first-degree murder conviction. Jurors had two options on the first-degree charge: either concluding Brazill planned to shoot Grunow, or killed him while committing burglary because he entered the school illegally to threaten the teacher with the pistol. In the second option, "felony murder," the killing did not have to be premeditated.

By finding Brazill guilty of the second-degree charge, the jury determined that the shooting was not premeditated.

Brazill's family rejected a plea offer from prosecutors before the trial that called for 25 years in prison in exchange for pleading guilty to second-degree murder. Brazill's defense team sought a manslaughter conviction.

Prosecutors argued Brazill was a troubled teen who felt in control with the gun, which he had stolen a week earlier from his grandfather's house. They also said he was angry over the suspension and a failing quarter grade he was receiving from Grunow. The teen said he didn't know about the mark.

A classmate, Michelle Cordovez, testified that Brazill told her he was going to return to school and kill the counselor who suspended him.

"Watch, I'll be all over the news," she said Brazill told her, but she didn't take him seriously.

Brazill countered that he returned to school on his bike and went to Grunow's class to say goodbye to two friends for the summer. He said he got mad at Grunow because the teacher didn't take him seriously when he asked to talk to the two girls privately.

The defendant called Grunow -- married with two children -- one of his favorite teachers. Grunow and three other teachers had recommended that Brazill become a "peer mediator," resolving conflicts between other students.

Brazill said he pointed the pistol at the teacher and pulled back the hammer, putting a bullet in the chamber, so the teacher would know it was a real gun and be scared into letting the girls into the hallway.

The teen testified that he thought the gun's safety was on. He admitted on cross-examination that he pulled the trigger, but said his hands were shaking and it was unintentional. He said his eyes became blurry with tears after he shot Grunow, whom he called "a nice guy, a good teacher."

When asked by a prosecutor why he brought the gun to school, Brazill said he was only carrying it and didn't plan to use it.

Along with the recent Tate sentencing, the case focused attention on the state's juvenile crime system. In Florida prisons, there are 15 inmates who were ages 13 or 14 at the time of their crime and were convicted of first-degree murder, according to the state Department of Corrections.

Tate, who was 12 at the time of the crime, said he accidentally killed Tiffany Eunick while imitating pro wrestlers. The girl suffered numerous injuries, including a skull fracture and a severed liver.

Gov. Jeb Bush has said he would expedite a clemency hearing in the Tate case.

Tate's appellate lawyer, Richard Rosenbaum, said Tuesday the defense team was in the final stages of preparing the clemency petition and said he expected to file it with the governor's office by the end of May.

Bush, appearing at a bill signing at a Tampa elementary school on Wednesday, said his first thoughts have been with Grunow's widow and children and noted Grunow's dedication as a teacher.

The governor plans to sign next week legislation drafted in Grunow's memory that provide scholarships to the children of slain teachers, he said.

But Bush said he also believes that Brazill should not have been treated as an adult, even though the 14-year-old had been tried as one.

"There is a different standard for children," Bush said. "There should be a sensitivity to the fact that a 14-year-old is not a little adult."

The Associated Press contributed to this report