A District man who pleaded guilty to stabbing his estranged wife to death after she picked her children up at school was sentenced to 30 years in prison Friday.

Claude Kinney, 48, pleaded guilty in October to first-degree felony murder in the Sept. 12 slaying of Alecia Wheeler, 42, behind a Northeast Washington recreation center. Kinney was arrested shortly after the attack.

It’s unusual for defendants to plead guilty to first-degree murder. In court Friday, Renee Raymond of the D.C. Public Defender Service said her client did so to keep the children from having to testify. When she was killed, Wheeler was with her children, ages 1, 3, 5 and 9; the youngest three were Kinney’s, and Raymond said he treated the oldest as his own.

“My mommy is getting stabbed,” the 9-year-old yelled during the attack, according to authorities. Wheeler, who also had two adult children from a previous relationship, was killed on the 3-year-old’s birthday.

At Friday’s hearing, several of Wheeler’s family members urged D.C. Superior Court Judge Gerald I. Fisher to give Kinney a longer sentence. “All she wanted was to be protected and loved by this man,” said Felicia Sweet, Wheeler’s older sister.

“My sister got up every day and took care of her children. He took her from them,” said Lisa Gonzalez, another sister. “No child should have to go through that.”

Fisher commended Kinney for sparing the children a trial. Fisher called the attack “a momentary lapse of sanity” and pointed to Kinney’s “irrational rage and emotions.”

If the case had gone to trial and Kinney had been convicted, Fisher said, he was “confident” Kinney would have received a longer sentence.

Wheeler had picked up her children at Wheatley Elementary School when she walked through an alley behind the Joseph H. Cole Recreation Center in the 1200 block of Neal Street NE, prosecutors said. That’s where Kinney approached her and fatally stabbed her, according to authorities.

Gonzalez said Wheeler was heading to a shelter for crime victims after picking up the children. Before her death, Wheeler had filed at least two court complaints against Kinney — they described a pattern of domestic assaults — including one just one day before she was killed.

Kinney, a tall, stout man, apologized to Wheeler’s family at the sentencing.

“I’m sorry for what happened. I’m sorry in my heart. I’m sorry it happened in front of my children,” he said. “My children have lost their mother and their father. I regret it. I miss, and I love her.”