The 14-year-old convicted of murdering his teacher took the stand Thursday in an attempt to convince the court that he should not spend the rest of his life in prison.

Nathaniel Brazill apologized to the victim's widow and called the person he shot to death a "great man and a great teacher."

Brazill shot 35-year-old Barry Grunow at Lake Worth Middle School in May of last year. The teacher had refused to let the then seventh-grader talk to two girls in his class. Brazill returned to school after being suspended by a counselor earlier that day for throwing a water balloon and shot Grunow.

"Words cannot really express how sorry I am, but they're all I have," Brazill said.

"As I look back on that day I wish it had not happened and that I could bring Mr. Grunow back," he said, reading from a statement.  "Regardless of what anyone thinks, I never intended to harm Mr. Grunow."

The teenager took the stand after the victim's mother and brother testified that Brazill should spend the rest of his life in jail.

"This was not an accident. I think Nathaniel should be punished to the fullest extent of the law," said Phyllis Grunow, the victim's mother.

Earlier in the day, Brazill's mother Polly Powell begged the judge for leniency, saying that "We know he's done something wrong. I've said that from the beginning and we know he must be punished."

Brazill was tried as an adult and convicted of second-degree murder in may. He faces from 25 years to life in prison.

Grunow's widow, Pam, told the judge that she didn't have a recommendation to the court.

"I do not know what price Nathaniel should pay for taking Barry's life," she said, reading from a brief written statement. "I cannot make a recommendation because that is not my job. I do not have the wisdom."

She described her husband as loving and a wonderful father with many friends and students who cared greatly for him.

"At home he enjoyed working in his garden and being Daddy," she said. "He was devoted to us. We were his priority."

The first witness for the defense said Brazill was a "pot boiling over" following his suspension on the last day of school and after years of silence about the physical abuse of his mother by boyfriends.

On the afternoon of the shooting, Brazill was preoccupied with seeing his first girlfriend after his suspension, said Jacqueline Patterson, deputy superintendent of Milwaukee schools.

"All this other stuff was exploding inside of him," she said.

Palm Beach County Sheriff's Lt. Mark Chamberlain, who guarded Brazill during his trial, testified that the teen seemed to have two different sides, acting appropriately in the courtroom but then acting like a hardened criminal elsewhere.

Once, he said, Brazill wanted to hurry back to the jail. When Chamberlain said that when he asked why, Brazill said he wanted to watch Con Air, a movie about prisoners who hijack a plane taking them to a maximum-security prison, and "learn how to be a better criminal."

"I replied 'What, are you a thug now?' He said, 'No, I'm not a thug. I just want to learn how to be a better criminal and I want to learn how to get out of handcuffs,'" Chamberlain said.

Following the hearing, Circuit Court Judge Richard Wennet will decide whether the teen can be rehabilitated. Wennet has said he may not rule until a few days after the hearing.

The Associated Press contributed to this report.