A man stabbed his wife and three children to death in their family home in Honolulu before taking his own life on Sunday, police said, in one of the deadliest crimes in Hawaii’s capital.

None of the victims have been named, but police said the children were aged 10, 12 and 17. All five were pronounced dead at the scene.

Honolulu Police Department Lt. Deena Thoemmes said at a news conference that officers were called to reports of an argument at a house in the city’s Manoa district around 9 a.m. Sunday and found five people dead.

The identities of the dead will be released in a report from the medical examiner’s office, police said.

“Based on the evidence found at the scene and the investigation thus far, it appears that the adult male killed the female and the juveniles with a knife that was recovered from the scene. The motive is still under investigation,” Thoemmes said.

She added that based on evidence found so far, “these don’t appear to be random acts.” Police are interviewing neighbors and reviewing security camera footage to find out more.

Thoemmes said the killings represented the most deadly crime in Honolulu since seven people were shot dead at a Xerox Corporation building in 1999, still the worst mass shooting to take place in Hawaii.

HPD Chief Arthur “Joe” Logan said at the same news conference: “I’d like to give our heartfelt condolences to the families. It’s unfortunate and very sad.”

He said he visited the crime scene to ensure that his officers were “mentally and physically fit to do their job, which they are.”

Logan also said that officers were first called to the house at 8:30 a.m. and may have knocked on the door and spoken to someone, but then left without taking any further action — only to return soon after, following another 911 call.

“So really they didn’t have enough information to make entry into the dwelling until we came back at 9 a.m. and spoke to another witness who provided more information,” Logan said.

He added that a crime this brutal “doesn’t happen in Hawaii very often.” He said the scenes inside the house will stay with the officers who responded “for the rest of their lives.”

Honolulu Mayor Rick Blangiardi said in a statement that he was “heartbroken by the tragic incident … claiming the lives of an entire family, ” Hawaii News Now reported.

Hawaii News Now spoke to neighbors who describe the so-far unnamed family as normal and typical, describing how they would put up decorations for festivals and let the children play in the street.