A four-year-old boy and his father are dead, and the mother critically injured, in an apparent murder-suicide in Las Vegas, Nevada.

According to the Las Vegas Review-Journal, the suspect, a man in his twenties, forced his way into his ex-girlfriend’s home on Wednesday evening and restrained her and their four-year-old son with zip ties before repeatedly stabbing them.

The suspect was found in the bathroom of the home with self-inflicted stab wounds.

The child’s grandmother, who was reportedly at the residence, called 911 and was able to get her daughter and grandson out of the house. She reportedly drove both victims to the hospital, where the boy was pronounced dead.

The woman is reportedly expected to survive although police told the Las Vegas Review-Journal that she suffered “significant stab wounds to her face and neck.”

“I don’t have words to explain another incident like this,” Metro Lt. Dan McGrath told the newspaper. “We’ve had too many of these. As a community I think, we really need to come together because of innocent people and children losing their lives.”

A motive for the apparent murder-suicide is not yet known, and the suspect and victims have not yet been identified.

An earlier report identified the four-year-old victim as a female, but later reports indicate the murder victim was a boy.

According to the Las Vegas Sun, the suspect had been charged with domestic violence against the woman in 2015, but did not have a restraining order against him.

“It’s a tragedy. I can’t explain how someone could kill their child; it’s very hard to understand,” Lt. McGrath told reporters from the scene.