The more Abigail Bautista tried to convey her pain, the harder it was to do so.

“I’m dying inside,” she said Thursday afternoon, speaking to a judge inside a Maryland courtroom.

In front of her, 30 feet away, sat Leonardo Siguenza-Neiros, a 22-year-old MS-13 gang member who had taken part in the savage murder of her son and was about to be sentenced for the crime.

“He cannot be let out,” Bautista told the judge. “I want him to pay for what he did.”

Denis Montufar-Bautista's death in late 2015 shattered his mother's life. She struggled to recover in part by taking a defiant posture toward the gang — refusing to leave the neighborhood of Langley Park where she and many gang members lived. This week Bautista shared her story with The Washington Post, describing widespread fears among Langley Park residents over the gang, and detailing her own experience of paying them $60 in weekly extortion so she could sell clothes, shoes and other items out of her apartment and from a cart she pushed through the neighborhood.

Leonardo C. Siguenza-Neiros was sentenced in the death of Denis Vitalino Montufar-Bautista. (Montgomery County Police Department)

Sitting at the sentencing hearing Thursday, though, meant listening to excruciating details about how Denis was killed: MS-13 members, under the guise of smoking marijuana, had lured him down a dark path just north of Langley Park. Then, next to a frigid stream, they suddenly attacked. Denis was punched, kicked and stabbed as he crawled to the stream. Then at least two of the gang members started picking up large rocks and chunks of concrete and slamming them down onto his skull. Denis fell into the water, where he died.

His mother spoke about him in court — how he wanted to study, how he helped her with a younger child. But the words became more halting, the pauses longer. She swayed in her chair.

“I just beg you to help me,” Bautista told the judge.

Then she leaned back, seemingly unable to breathe, with those around her talking about her having just fainted.

Bailiffs quickly walked to her. Paramedics were summoned. The hearing was put on hold. But 25 minutes later it resumed, and a short time after that, Montgomery County Circuit Judge Cheryl McCally delivered her sentence: life in prison.

“This was a senseless, brutal, calculated slaughter for reasons known only to you and your gang associates,” she said.

She spoke to Siguenza-Neiros about the way Denis had died — still alive in the water, ultimately succumbing to stab wounds to his torso, crushing wounds to his head and drowning.

“What I know is that this young man did not deserve to die feeling the pain of every one of those wounds,” she continued. “He did not have the privilege of dying instantly. He suffered. You know that because you were there.”

Moments earlier, Siguenza-Neiros had spoken briefly to the judge.

“I would like to say that I’m sorry for what happened to Denis,” he said. “I feel remorseful for what happened. If I could go back in time I would do things differently. I’m going to be thinking about it for the rest of my life.”

Siguenza-Neiros, born in El Salvador, entered the U.S. illegally as a teenager, was placed into the U.S. program for unaccompanied minors, and made his way to Maryland, according to authorities.

The hearing also addressed broader issues of MS-13, an international gang with ties to El Salvador that is responsible for gruesome murders in and around the Washington region in the past few years.

“There is a path of destruction that you and MS-13 have caused,” McCally said. “It’s beyond the pale of what any community can tolerate.”

“We are in the middle of an incredibly violent crisis in Montgomery County,” prosecutor Patrick Mays said in court. “A huge part of that is the presence of MS-13. [The gang] is terrorizing our communities.”

He drew a connection between the violent murder of Denis and other homicides. This year, Montgomery County detectives found an MS-13 victim buried in the woods in Wheaton who had been stabbed more than 100 times, decapitated, and had his heart ripped out.

“MS-13 has clearly made it a point of sending a signal to our community that this how they want to exercise violence, this how they want to exercise control,” Mays said.

After the hearing, Bautista said she was satisfied with the sentence.

“That’s what I wanted,” she said. “Justice.”

She felt a pain in her heart, she said, seeing Siguenza-Neiros in court. She said she regained her strength because she knew Denis would have wanted her to.

“I know he’s with me,” she said. “And I’m close to him.”

Siguenza-Neiros had pleaded guilty last year to first-degree murder in the case. His attorney at the time, Timothy Clarke, said he was acting on instructions from those above him in the gang.

“If he did not participate in this murder, he would have been the dead person,” Clarke said.

On Thursday, a new attorney for Siguenza-Neiros, Gary Proctor, said his client did not play a central role in the attack. But he did slash Denis at least once, and he kicked and beat him, according to Proctor.

“The first time the police ever talked to him, he gave a full confession,” Proctor said.