A 15-year-old girl who pleaded guilty in the beating death of a 64-year-old disabled man in the nation's capital last year testified that she knew the victim was dead before she and four accomplices fled the scene, and that they carried out the vicious attack because they were bored and looking for something to do.

Reggie Brown, a frail man with physical disabilities who lived in Northwest D.C., was found beaten to death in an alley on Oct. 17, 2023.

After several months, police announced the arrest of several underage girls, one as young as 12, who allegedly chased Brown into an alley and pounded him to the ground until he was dead.

None of the five defendants have been identified publicly because they are minors.

The 15-year-old prosecution witness, the eldest of the group, has pleaded guilty to a reduced charge of assault with a dangerous weapon. In exchange for her cooperation, she has received a sentence of three years in a juvenile detention facility, according to reports.

In March, police arrested the 12-year-old and two 13-year-old girls, followed by the arrests of the 14-year-old and 15-year-old in July. All five were charged with second-degree murder for their alleged involvement in Brown's death.

If convicted, the two girls currently on trial could face a maximum sentence of being detained in a juvenile facility until they turn 18, in accordance with D.C. law.

The trial judge also indicated that another defendant had since pleaded guilty, although further details about the plea deal have not been disclosed.

Exactly one year has passed since the fatal beating.

During her testimony, the 15-year-old revealed that she had proposed to the group that they look for someone to beat up because she was feeling bored.

She also testified that they realized they had killed Brown as they walked away .

Moments before their involvement, the girls reportedly came upon a fight between Brown and a younger man in his 20s, who already had the old man down, then invited the girls to come finish him off, which they did with brutal enthusiasm, police said.

Brown found himself overmatched and outnumbered, unable to defend himself.

He tried to run but the teens chased Brown into alley, and as he tried to climb up a chain fence, pulled him down and stomped his head into the pavement, police said. After this, they pulled his pants down around his ankles, removed his belt and beat him with it, according to previous reports.

The girls, barely old enough to be out alone, allegedly sauntered off into the night, leaving Brown in a pool of his own blood, police said.

The 12-year-old assailant reportedly recorded the beating on her cellphone, which has since been played in court, showing one of the youngsters mocking Brown for bleeding too soon, saying, "Damn, you leakin'!"

One of the girls told police that two of them did not want to take part in flogging, but was forced to after Brown threatened to shoot them.

Brown had mental health issues, a metal plate in his head and only two fingers on each hand, reports said.

After police arrived, he was pronounced dead at the scene.

A medical examiner concluded that Brown died as a result of a homicide due to blunt force trauma to the head, which resulted in brain bleed.

Even after Brown's death, the case has seen additional instances of violence.

The 12-year-old suspect was shot in the leg during an unrelated incident at her home in late March before she was arrested, although the injury was non-life-threatening.

In July, the 13-year-old defendant allegedly sucker-punched a U.S. marshal during pretrial proceedings, leading to her arrest and removal from the courtroom on a stretcher.

In another twist, all three girls lived in the same suburb of Northwest D.C. as the victim, but there was no indication they ever crossed paths before the night Brown was slain, police said.

On the night of Brown's death, detectives came upon a man's lifeless body in the middle of the night on Georgia Avenue.

Investigators said Brown's attackers didn't know him, leaving relatives struggling to make sense of the violence that claimed his life.

"My uncle really didn't deserve this," Brown's niece told News4 in Washington earlier this year. "He was known in this community for years, so for this to happen where he lived for 64 [years] is insane. They have to be held accountable."

Brown's beating death coincided with a similar case in Philadelphia where adult charges were dismissed against two teen suspects who were accused of beating an elderly Black man to death with a traffic cone in 2022.