Mauricio Morales-Caceres, left, was sentenced Friday for killing Oscar Navarro, right, in a Silver Spring, Md., townhouse. Navaro was stabbed and slashed 89 times. (Courtesy of the Montgomery County State’s Attorney’s Office and the Navarro family)

What Mauricio Morales-Caceres did displayed a level of depravity rarely seen by investigators: Armed with a 15-inch butcher knife, he stabbed and slashed a friend 89 times, pulled out his liver and left it on the dead man’s chest.

On Friday, the 24-year-old was sentenced to life in prison without the possibility of parole after a hearing in Montgomery County Circuit Court.

As the case against him came to a conclusion, new documents showed how in the days after the killing, Morales-Caceres didn’t think that he had done anything wrong at all.

He made his way to a favorite taco food truck, where he had often hung out with the victim. The owner asked Morales-Caceres where his friend was.

“He just laughed,” prosecutors wrote.

A 24-year-old man was convicted of first-degree murder after stabbing and slashing an acquaintance at least 89 times. He faces life in prison. Hear the previously released 911 call made after the stabbing. (Montgomery County State's Attorneys Office)

A few days later, when detectives solved the case, arrested Morales-Caceres and took photos of him, he smiled for their camera. And after being placed in a jail, he wrote graffiti for a deadly street gang — MS-13 — on his cell walls.

“The defendant,” prosecutors wrote, “is maniacal and inherently dangerous.”

At his sentencing hearing, they asked Judge Mary Beth McCormick for the life term with no chance of parole. Morales-Caceres’s attorneys, citing his youth and limited criminal record before the murder, had sought a term of 25 to 35 years.

McCormick was unflinching in imposing life without parole, telling Morales-Caceres: “I can’t see a reason to think that parole should be in your future.”

She continued: “But you asked for this sentence. I did not. And I just can’t see that you should ever walk on this earth. Whether it be in El Salvador or in America, you cannot be safely maintained on this earth. And for this crime, you got what you deserved.”

The court documents fall short of explaining a motive for the Dec. 23, 2014, killing of Oscar Navarro, 36, in a Silver Spring townhouse, leaving open whether Morales-Caceres had a clear reason. The case also adds to the violence committed by individuals whom county law enforcement officials say are associated with resurging crimes committed by MS-13.

The documents, including those filed by Morales-Caceres’s attorney, establish that he was exposed to harsh violence growing up in El Salvador. When he was about 8, a relative “attempted to murder each and every member of his family in a vicious attack with a machete,” defense attorney Emily Beckman wrote. “Mr. Morales-Caceres sustained a laceration during the onslaught.”

Here is what you need to know about MS-13, a street gang with an international reach. (Claritza Jimenez/The Washington Post)

He came into the United States illegally in 2013, made his way to Montgomery County, and by 2014 was associated with MS-13, according to prosecutors.

Earlier: 89 stab and slash wounds, excised liver test jurors’ endurance

That year, police were called about a possible fight in progress at an apartment in Silver Spring. Finding Morales-Caceres and two others arguing outdoors, officers told them to put their hands behind their heads, but they got no response as the three continued to yell and shove each other, according to court records.

The officers eventually put Morales-Caceres in handcuffs and spoke to the person who had called police, who told them that Morales-Caceres and his brother had been arguing over a cigarette. He had told them to calm down, and the pair then turned on him, according to a police account in court records.

Officers charged Morales-Caceres with being drunk in public, disorderly conduct and resisting arrest. He was released from jail on his own recognizance, and the case was later dropped when he agreed to perform community service, according to court records.

Later that year, in December, he got “503” tattooed on his calf. Many members of MS-13 identify with the numbers, according to prosecutors, because they are the country calling code for El Salvador. Investigators said they later found MS-related text messages and images on his cellphone.

At Morales-Caceres’s trial in April for the murder of Navarro inside Navarro’s townhouse, prosecutors proved that the attack was premeditated. In documents filed for sentencing, they described it as an ambush.

“Once inside Oscar’s house, the defendant was friendly enough that Oscar trusted the defendant and turned his back on him,” Assistant State’s Attorney Stephen Chaikin wrote. “The defendant reached into his clothing and grabbed the knife.”

The subsequent attack and mutilation of Navarro — followed by the cavalier reaction in the days afterward — have racked Navarro’s family, including his children, now 11 and 12.

“They’re kind of healing,” Navarro’s widow said in an interview Thursday, explaining how she has worked to shield them from the gruesome details of the crime. “To really know what happened would devastate them right now.”

The woman, who for safety reasons asked not to be identified, said their daughter just finished elementary school. “Mom, I really wish Daddy was there to see me graduate,” she told her.

The girl cheers herself up by looking at photos and videos of her dad on her mother’s phone. “Mom, can we just look at all the little pictures again?” the girl will say, according to her mother.

Her son doesn’t talk much about his father’s death, she said. Earlier this year, he was riding in their car and started to cry. “I don’t want to play soccer anymore,” he told his mother, “because Daddy isn’t here to play with me and teach me.”

She pulled over, stopped the car and hugged him.

The children wrote letters about their father to McCormick, the judge, as part of the victim-impact statements submitted for sentencing.

“I just wish I can see him one more time,” Navarro’s daughter wrote, “and grab him so hard and never let go.”

His son spoke about the game his dad taught him.

“I stopped playing soccer for a while,” the boy wrote. “But then I realized, what would my dad want me to do? So I started to play soccer again for him.”

Said Nelson Navarro, Oscar’s brother: “This guy really has demons, and he belongs in prison. I want to make sure my brother is the last victim to suffer by his hands.”