A SCHOOLBOY who beheaded and hacked up his classmate in a jealous rage "with a pocket knife" has been given two life sentences.

Matthew Borges - just 15 at the time - was convicted of murdering and dumping the dismembered body of his 16-year-old friend Lee Manuel Viloria-Paulino, all because he talked to his girlfriend.

7 Mathew Borges was convicted of the first-degree murder of Lee Manuel Viloria-Paulino Credit: NBC

7 Lee’s body was found in December 2016 by a woman walking her dog Credit: Facebook

Lee's body was found by a woman walking her dog on the banks of the Merrimack River in Massachusetts in December of 2016.

On Tuesday, Lee’s mother Katiuska Paulino made a tearful tribute to her son during the sentencing hearing at Salem Superior Court in Lawrence, Massachusetts.

She asked for Borges to spend the rest of his life in jail, saying he "deserves to spend his life incarcerated so at the very least, it serves to keep him off the streets," WCVB reported.

She added: "He should never have the opportunity to kill again, to rob another person of their life like he did Lee Manuel, in such a horrible and sad way."

Judge Helene Kazanjian refused to set a minimum prison term for Borges because of his age when he committed the crime, meaning he may be eligible for parole in years to come.

Borges remained silent during his sentencing.

'RIPPED FROM OUR SIDE'

A victim impact statement read in court by Lee's mother described Lee as "a sincere, loving, responsible, charismatic, and altruistic young man on the verge of seizing life and many, many goals".

"There are no more dreams for the dreamer, the brother, the writer and the poet that was Lee Manuel Viloria-Paulino…

"He has been the soul of this family since he was born.

"We are the living dead after he was brutally ripped from our side."

'DEAD EYES'

Two of Borges’ ex-girlfriends spoke about his jealous streak during the trial.

Stephanie Soriano, 18, read text messages she said he sent her before the murder.

She said he often spoke of his “demons” and once sent her a message that read: “I think of killing someone and I smirk.

"It’s all I think about every day but I control myself ... I like the sound of it - the idea of causing pain in someone getting in my way or causing me pain.

"I see people I don’t like [and] that comes to mind. I’m going insane.”

Eyes that are dead are scary... Eyes that don’t shine, that are full of darkness." Mathew Borges

The day before Borges killed Lee he asked Soriano if his eyes looked dead.

He then sent her a 48-second voice memo, which was played in court.

In the recording Borges can be heard saying: “Eyes that are dead are scary...makes you think about what that person has done. What they’ve been through. What they’ve seen. Eyes that don’t shine, that are full of darkness.

“It’s just sad. It’s like these people are different. They’ve done things that make them lose their humanity. Like they have no soul they just have big black pupils.”

He then told Soriano to look carefully at his eyes the next time she saw him as he, too, would have dead eyes soon.

He told her: “That may as well be the last time you see them like that again."

Another one of Borges' former girlfriends Leilany Dejesus, now 18, previously testified that he was consumed by rage and jealousy when he saw her talk with Lee at Lawrence High School.

She said that Borges was so angry that at one point the school dean had to escort him from the cafeteria, WBTS-TV reported.

'POCKET KNIFE WITH DRAGONS'

Prosecutors said Borges was seen on surveillance video walking toward the river with Lee on the night of his death.

The pair went to the riverbank to smoke marijuana, after which his family reported him missing the next day.

While the two teens were out by the river, a group of four of Borges’ friends broke into Lee’s home.

The other boys allegedly told police that Borges planned to kill him.

Prosecutors also alleged that a note found by investigators reveals how Borges planned to carry out the murder.

Sections from Borges’ high school journal were read by prosecutors during the trial.

On November 16 of 2016 - two days before Lee went missing- Borges wrote: “Go chill with him at his crib alone. Drink smoke and play it off.

"Kill him call JM and Scooby tell them pull up then take everything.

“Bring duffle bags. Wear gloves clean up mess. Wear bags on shoes. Wear clothes you don’t care about.”

Investigators said Borges cut his Lee's head off so the body would not be recognised.

Although police never found a murder weapon, DNA or blood evidence, prosecutors said Borges likely used a pocket knife with dragons on it that he often bragged about to his friends.

7 Lee’s mother Katiuska Paulino made a tearful tribute to her son during the sentencing hearing Credit: WCVB5

7 Borges' then-girlfriend Leilany Dejesus, now 18, testified that he was consumed by rage Credit: WBZ

7 Borges has been given two life sentences for murdering his classmate in a jealous rage Credit: North of Boston Media Group ©2016

7 Lee Manuel Viloria-Paulino was just 16 years old when he was murdered Credit: Facebook

7 The body of 16-year-old Lee Manuel Viloria-Paulino was found on the banks of the Merrimack River in Massachusetts, US, in 2016 Credit: NBC

Opening statements in trial of Matthew Borges, 15, who 'beheaded classmate in jealous rage for talking to his girlfriend'