The sentencing of a man who had just pleaded guilty for killing his three children in a house fire was interrupted Thursday when a woman dashed across a courtroom and beat defendant Joseph Washington to the ground.

Washington, 30, purposefully set the Oct. 18 blaze that claimed the lives of 3-year-old Avery Washington, 5-year-old Jayla Washington and 8-year-old Joseph Washington, authorities alleged.

On Thursday, he pleaded guilty as charged to three counts of first-degree murder and obstruction of justice. In exchange, prosecutors agreed not to seek the death penalty against him.

But before Orleans Parish Criminal District Court Judge Nandi Campbell could sentence Washington to mandatory life in prison, a family member of the slain children ran across the courtroom to Washington, punching him until he fell to the ground.

Other family members joined in. Deputies spent minutes untangling the bodies that had piled on top of Washington.

No one appeared seriously injured.

After the instigating family member was taken into custody and the remaining family members removed from the courtroom, Campbell sentenced Washington to mandatory life in prison.

According to New Orleans police, Washington threatened to ignite the house in the 4900 block of America Street in the moments before the first flames were reported. The children’s mother, who is also Washington’s ex-wife, called 911 to report the threat, police said. She was not home at the time.

Though New Orleans firefighters quickly battled the blaze, one child died inside. Two more perished at a local hospital.

Washington also pleaded guilty Thursday to one count of obstruction of justice.

Separately, Shanyka Phillips is charged with being an accessory after the fact, for allegedly aiding Washington in his attempts to flee and hide from law enforcement after the fire.

She has pleaded not guilty and is being held in New Orleans jail without bail, court records show.