Father, 34, kills his two kids, 7 and 6, and himself in horrific murder-suicide using a rifle that was eerily found place across his lap

An Arizona father has killed his two small children and himself in a horrific murder-suicide amid a divorce battle.

Brock Mater, 34, his son, seven, and daughter, six, were found shot dead inside their home in Surprise, a Phoenix suburb, on Monday.

Police said they found the murder weapon - a rifle - across the father's lap.

Mater had been undergoing mental health treatment before the murders, KTAR News reported. 

Officials were alerted by the children's mother Hope Mater, who became concerned after receiving a call from their school saying they did not show up. 

Brock Mater, 34, his son, 7, and daughter, 6, were found shot dead inside their home in Surprise, a Phoenix suburb, on Monday

Hope tried knocking on the home's door multiple times without response. She called police after noticing Mater's car in the driveway. 

The couple were going thorough a divorce and the children had been visiting Mater over the weekend. 

Mater's sister Larissa Mater asked for prayers for her family in a Facebook post on Wednesday.

The couple were going thorough a divorce and the children had been visiting Mater over the weekend

Hope tried knocking on the home's door multiple times without response. She called police after noticing Mater's car in the driveway

She wrote: 'Please pray for my family and Hope Mater. My brother Brock Mater and his kids will be mourned and missed.'

Hope had filed a protective order against her estranged husband last fall, arguing he had been abusive to her and threatened to kill himself after she asked for a divorce, according to Fox 10. 

In the petition, Hope mentioned Mater owned guns and asked that they be banned from possessing firearms.

Hope had filed a protective order against her estranged husband last fall, arguing he had been abusive to her and threatened to kill himself after she asked for a divorce

Hope also said Mater was 'speaking of demons and cults and was highly agitated and fearful.'

A week after she filed the petition, Mater took the children out of school and drove them to a hotel without informing their mom, per the divorce filing. 

Mater then called police saying he was suicidal and homicidal and was taken to a hospital on a psychiatric hold. 

Hope asked for the order of protection to  be dismissed on May 1, as the divorce was nearly finalized.