Video (01:22) : The guilty plea came after months of Collins denying he had any role in his 10-year-old son Barway's disappearance and death.

Hours before 10-year-old Barway Collins was reported missing, his enraged father punched him until he was unconscious, duct-taped his body and threw him into the Mississippi River.

"I killed my son," Pierre Collins said Monday in Hennepin County District Court, describing his actions on March 18 outside their Crystal apartment building after the boy had been dropped off by his school van. "I hit him and he fell."

After months of insisting that he had nothing to do with the boy's disappearance and death, Collins, 33, pleaded guilty to second-degree intentional murder before a packed and emotional courtroom. He was sentenced to 40 years in prison.

Barway Collins' body was found in a stretch of the river in the north metro on April 11. His death, the almost-two-week search for his body and the charges against his father have been a confusing, wrenching experience for the Twin Cities' large Liberian-American community. Monday's plea negates the need for a trial that had been set for January.

Collins, who originally had faced first-degree murder charges, was given a longer sentence than is called for by state guidelines because Barway was vulnerable and because hiding his body was particularly cruel, said Hennepin County Judge Tanya Bransford.

His "actions caused great pain … to the whole community," she said. "It is unimaginable that a parent would kill their own child."

Barway Collins' mother, Louise Karluah, left, and his stepmother, Yamah Collins, hugged each other after attending the Monday court hearing.

Collins' confession of how he became angry with his son, beat him, then dumped him into the river drew gasps and cries from courtroom observers, including Yamah Collins, Barway's stepmother; Louise Karluah, Barway's birth mother, who traveled from Liberia after his death, and Pierre Collins' former wife, Jennifer Beaver, the mother of four of his children.

All three women took care of Barway at some point. Karluah and relatives cared for him in Liberia before he was sent at age 5 to the United States to join his father, who had emigrated. Beaver cared for Barway during her marriage to Collins, but was unable to get custody of him when they divorced. She is the mother of two children with Collins, who also adopted her two children from a previous relationship. Yamah, Collins' current wife, the mother of two other children, cared for Barway most recently.

At one point, Karluah fell from her chair in shock and grief. She later was escorted into a hallway before returning to make an unplanned victim-impact statement. She was unable to speak clearly, so a friend, Victoria Peabody, took the stand to say they are both "broken and lost."

"I went to Mr. Collins' house and prayed with him," Peabody said. "I just feel so dirty because I held his hand. … Louise is so lost."

Karluah said she forgives Collins and is relieved that he pleaded guilty. She said that if Collins hadn't wanted their son, he should have sent him back to his native Liberia. "It's not right. Not feeling good right now. … I've been praying for justice," Karluah said. "Barway is a very special child to me."

Yamah Collins and Beaver separately embraced Karluah before and after the hearing.

Beaver, who has alleged that Collins abused her and their children, said she cannot forgive him.

"Just hearing him say that he murdered my son — how could you do that?" Beaver said after the hearing. "So you mean to tell me you beat him so bad and you duct-taped him and threw him in the water like nothing?"

Yamah Collins, who had stood by Pierre's side since Barway's disappearance, shook her head and walked away when asked if she would continue to support him.

'We found justice for Barway'

In confessing to Barway's murder, Collins told the judge that he became angry with the boy when he misbehaved as he played outside after arriving home from school. "I was really mad at him," Collins said. "I hit him … he fell. He wasn't responding, so I took him to the water. … I intended to kill my son."

Collins said he was fearful because he knew he would be in trouble, so he taped the boy's arms and legs and threw him into the river in an attempt to hide the body.

He also asked for sympathy, saying, "I want everybody in the community to forgive me." But afterward, some of his family members said they were dismayed that it took him so long to tell the truth and disappointed by the plea deal.

County Attorney Mike Freeman said after the hearing that Barway's body remained underwater until he was found 26 days later by volunteer searchers. Authorities have not been able to establish an exact cause of death.

The guilty plea brings "some justice for Barway's family," Freeman said.

"The last thing we know that Barway Collins said is, 'There's my dad,' " Freeman said, referring to video footage of Barway taken in his school van. "And he said it in a voice of being excited to see the person he loved. He's gone. None of us can explain or comprehend how a father could kill his son. We don't know exactly what happened … [but] there's some justice for Barway's family and for little Barway, as well."

Barway Collins' mother, Louise Karluah, attended the court hearing Monday at which Barway's father, Pierre Collins, pleaded guilty to killing the 10-year-old boy.

Crystal Police Chief Stephanie Revering, who joined Freeman at the news conference, said Monday was the "culmination of our search for justice for Barway Collins." Crystal police, with help from other agencies, searched for the boy for weeks "hoping to bring him home safe, but knowing that someone close to him was likely responsible for his disappearance," she said.

"We can never bring him back," Revering said. "But today we can finally close this case knowing that we found justice for Barway."

Twitter: @KarenAnelZamora