RENO, Nev. (AP) — A Nevada man convicted of murdering his pregnant girlfriend on the Pyramid Lake Paiute tribal reservation nearly three years ago has been sentenced to life in prison plus 20 years.

Michael Burciaga, 36, was sentenced Monday, prosecutors said. He was convicted by a federal jury in June of first-degree murder on tribal land, plus domestic assault by a habitual offender and violating the Protection of Unborn Children Act.

The 37-year-old victim was identified only by her initials, A.D.

Prosecutors said the horrific stabbing attack in December 2020 was witnessed by the woman’s children.

Burciaga confessed to the killing when he returned to the scene of the crime hours later after harming himself, according to authorities.

Burciaga stabbed his girlfriend multiple times with at least two knives at her home in Nixon, northeast of Reno, prosecutors said.

The victim’s 15-year-old daughter was one of three children at the home during the attack and called police to report that her mother’s boyfriend had stabbed her.

According to the FBI, Burciaga came back to the home while Pyramid Lake tribal police were investigating, telling them: “I already know what happened, and I know what I did.”