Kareem Leiva, Anthony Avalos, Heather Barron (Images via ABC 7 screengrab)

A girlfriend and boyfriend from Lancaster, California convicted of the "unimaginable" torture murder of the woman's 10-year-old son, Anthony Avalos, were sentenced to spend the rest of their lives in prison without the possibility of parole.

Heather Maxine Barron, 33, and Kareem Ernesto Leiva, 37, appeared before Los Angeles County Superior Court Judge Sam Ohta on Tuesday to learn their punishments for first-degree intentional murder and torture. Before the two were found guilty in March, prosecutors told the presiding jurist that the two defendants are "evil" and "sadistic."

"Kareem was the enforcer, Heather was the mastermind," Los Angeles Deputy District Attorney Jon Hatami said during closing arguments. "Heather came up with the torture techniques and she got Leiva to do them."

"They are bad, evil people — and I use the word 'people' lightly because they are nothing short of monsters," he added.

According to the Los Angeles County DA's Office, deputies found Anthony unresponsive at the home in Lancaster after a 911 call on June 20, 2018. The boy died at a hospital the next day — and officials determined Anthony had been severely abused physically in the weeks before he died of dehydration and blunt force trauma injuries.

The judge overseeing the bench trial agreed that the evidence showed Anthony Avalos was tortured to death and that Barron and Leiva "derived pleasure from seeing Anthony suffer."

"The acts of knowingly preventing Anthony from access to liquids involve each defendant actively keeping Anthony's bedroom door locked for the substantial duration of the period required to cause the severe dehydration, or when Anthony was not locked in his room. For each, to vigilantly watch him or prevent him from access to liquids," Ohta said, according to ABC 7. "Evidence adduced at trial shows both defendant Leiva and Barron at separate times independently went into Anthony's room. This meant each had to lock his door when each exited. This was clearly a purposeful and coordinated action by both the parents meeting the requirement of willfully."

Barron and Leiva were also convicted of abusing Avalos' two half-siblings after it was alleged that the children were forced to kneel on nails or uncooked rice for extended periods, were forced to squat until they collapsed, were force-fed hot sauce, were locked in their rooms for days, and were deprived of food and water. If the children urinated or defecated in their rooms, Leiva shoved their faces into their waste, the Los Angeles Times reported.

"The brutality that was meted out on this young child was unimaginable. No child should endure this kind of violence and torture at the hands of the people who are supposed to love and protect him from harm," LA County District Attorney George Gascon said in a statement after the bench trial verdict. "The actions taken by the defendants were truly revolting, and I am thankful that they will be held accountable."

On Tuesday, the murder convicts looked on as several of Anthony's grieving family members delivered emotional victim impact statements (h/t Fox 11).

Anthony's sister Destiny was the first one called to make a statement, but she was not immediately able to do so. Crying was audible in the courtroom. The victim's 8-year-old cousin Matthew stood at the microphone next and said he was a baby when he last saw Anthony alive.

"My name is Matthew Barron and I am 8 years old. I miss my cousin Anthony. I was a baby when I last saw him. I wish I could remember all our time together. But all I have is pictures and stories that my family tells me. Anthony was full of life and love. He always played with me and made me laugh. I have family and I have a video that I like to play over and over from him making me laugh," Matthew said, reading his statement from a piece of paper. "When I was little, we were about five. We will never get to see Anthony grow up. I will never get to play with my older cousin."

The boy called his aunt Heather an "evil monster," refused to forgive her, and hoped she gets beat up in prison. He also hoped the defendants "burn in hell."

"Heather, who's supposed to be my aunt, took Anthony away from us. Heather is an evil monster and she deserves to spend the rest of her life in prison. I don't forgive Heather for taking my cousin's life, and I hope she gets beat up in jail," Matthew said. "I hope Heather has a horrible life. Anthony's in a better place. And someday we'll be together again, and we will be able to make new memories. I always carry you (Anthony) in my heart and miss you very much. Thank you for your time."

Destiny, now 13, said in a statement that Anthony was her "best friend" and her "whole world."

"Because of these two monsters, he is not here anymore. Anthony did not deserve any of the things that happened to him," she said, according to FOX 11. "I am a 13-year-old girl. I should not have to be here doing all this. I should be able to live a normal life."

"To me, you are both monsters and Heather, you're not my mother," Destiny added. "If I knew that the abuse would have ended with me losing my brother, I would have said something. But I didn't, because I was scared and terrified. And I'm not anymore … I have learned to accept it. You guys can't hurt me anymore. I'm finally free from all the torture and abuse. And if I were to have known that this would end with me losing a brother, I would do it all over again with just one difference – that it would be me. Thank you, your Honor."

In a statement to Law&Crime on Wednesday, DA Gascon said that Anthony Avalos' death is "a painful reminder of the devastating impact that child abuse can have on our communities."

"We must do everything in our power to prevent child abuse and protect our most vulnerable children. This includes addressing any systemic failures that may exist within our child welfare and law enforcement systems. We must work together to ensure that every child is safe, loved, and cared for, and that no child ever has to endure the kind of abuse that Anthony suffered," the DA said. "My heart goes out to Anthony's family and loved ones. I know that there is nothing that we can do to bring Anthony back or undo the harm that was caused but I hope this brings them a small measure of peace."

Watch part of the proceedings below, including cousin Matthew's statement: