RIGBY, Idaho -

A man who killed another man at a 15-year-old's birthday party last summer may spend the rest of his life behind bars.

On Monday, Emmanuel Jesus Granados, 24, was sentenced to possibly life behind bars. After 20 years, a parole board will review the time he has served. If Granados has done well – meaning continuing with educational opportunities provided through the correctional facility, focusing on rehabilitation and not being involved with criminal activities in prison – he could be granted parole.

In February, Granados pleaded guilty in the July 14, 2013, death of 22-year-old Fermin Lemus. Under the plea deal, the charge was reduced from first- to second-degree murder, and the weapons enhancement to the charge was dropped.

Monday, an emotional Granados told Seventh Judicial District Judge Gregory W. Moeller that he was determined to become a better person. Moeller told Granados if he is serious about that, he will have to prove it in the next 20 years.

Granados walked into a full courtroom in Jefferson county Monday afternoon to hear his sentence. Granados told the judge he shot Lemus because he feared for his own life.

"I was just scared, your honor," said Granados.

He added that he had found God and is focused on changing his life for the better.

"I just ask God for him to make me change and be a better person," said Granados.

State Prosecutor Paul Ziel said the Lemus family had a statement to share about the impact of Granados' actions on their life.

Angelica Lemus, the victim's sister, came to the microphone.

Fermin Lemus had an unborn child when he was killed. The baby is now a healthy girl, but one who will grow up never knowing her father. Angelica Lemus' statement highlighted the life her niece will have without her father.

Emotionally distraught, she was unable to read the statement she wrote, and asked Ziel to do so.

"I hope one day you truly regret that you killed my brother. You took away his right to be a father, and the chance to see her grow up and give her hugs and kisses and see her grow up," read Ziel.

Ziel added Angelica Lemus had said both her brother and Granados were good kids who got into the wrong crowd.

Lemus' autopsy showed he had drugs in his system the night he was shot.

Lemus also had a criminal record. Ziel argued, unlike Granados, Lemus will never have the chance to become a better person.

"He was 22 years old. This was a person who had the chance to evolve and be better taken away from him prematurely," said Ziel.

Moeller called the crime "senseless, a savage monsterous act, so disturbing on so many levels."

He told Granados he has two options; to spend the next 20 years in prison finishing his education and focusing on rehabilitation or not using his time wisely and possibly spending the rest of his life in a prison cell.

Granados shot Lemus three times. Lemus was unarmed. 

Granados also has a young child. 

In addition to Granados' sentence, he will also have to pay a $50,000 fine and a $5,000 civil penalty, which will go directly to Lemus' daughter.