Honolulu police said Sunday they were investigating what appears to be the murder-suicide of a family, including three children, at a Manoa home.

Police first arrived at the home at 8:30 a.m. but left after no one answered the door, Lt. Deena Thoemmes said during a news conference Sunday afternoon. She explained the initial call was from an anonymous person and police had no cause to enter the home.

Officers returned at 9:15 a.m. after receiving another call and were able to speak with a caller. Upon entering the residence, they found four people who had been fatally stabbed and appeared to be a wife and three children aged 10, 12 and 17. The husband also was found dead.

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A preliminary investigation showed the husband fatally stabbed his wife and children, Thoemmes said. She added the husband’s cause of death was under investigation when asked whether he stabbed himself.

The ages of the adults was not immediately known. The medical examiner's office will release the identifications of the deceased.

There was no history of domestic calls to the residence and police did not have a motive for the killings, Thoemmes said.

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Witnesses reported there had been an argument in the home early Sunday morning, police said.

The five deaths mark the state’s worst mass killings since the Xerox murders on Nov. 2, 1999, when Bryan Koji Uyesugi fatally shot seven co-workers, including his supervisor, Chief Joe Logan said.

The horrific scene found Sunday will have an impact on the officers, Logan said, "as it would any officer, for the rest of their lives."