Two children in Colorado were killed after their older brother stabbed them in an early-morning attack Tuesday, Colorado Springs police said.

Police responded to the home around 1 a.m. and found three victims with apparent stab wounds.

The suspect’s siblings, 5-year-old Sophia Murphy and 7-year-old Noah Murphy, suffered stab wounds to their necks and were later pronounced dead.

A 19-year-old suspect, identified as Malik Vincent Murphy, was arrested and charged with two counts of first-degree murder, according to KDVR

The children’s father, Jefferson Murphy, is being treated for nonlife-threatening injuries and is expected to survive.

He told police he was confronted by Malik after going to check on one of his children screaming.

There were other people inside the home at the time of the stabbing and police are working to determine their relationship with the victims and Murphy.

In a police document, Malik Murphy revealed he often had “homicidal ideations,” and planned to kill his family and bury them in the backyard so he could be alone at the home.