The gunman in the New York murder-suicide was concerned that he would be excluded from the family's will, according to police.

On Sunday, a gunman in Long Island, New York, killed five people, including his three siblings and niece, after fearing he would be excluded from his family's will, according to police.

According to Nassau County police, Joseph DeLucia Jr., a 59-year-old mechanic, bought a shotgun legally before committing a crime after deciding to leave the home he had lived in for his entire life.

According to Det. Capt. Steve Fitzpatrick, who spoke on Monday, Joseph Jr.'s perception was that he was being excluded from the will and would be left without a place to go. He had a history of psychological issues.

DeLucia's family had gathered on Long Island to settle her will three days after her mother's passing.

The four victims had arrived to meet the realtor, bringing Starbucks. They were all assembled in the den area. However, Joseph DeLucia Jr. had stayed behind, Fitzpatrick stated.

According to police, DeLucia was reportedly terrified that he would be disinherited and forced to vacate his lifelong residence.

Fitzpatrick stated that DeLucia was being taken care of, but would have to relocate, causing him to panic.

On Sunday, at approximately noon, Nassau County police were called to Wyoming Court in Syosset where a man was found lying on the front lawn and shots had been fired.

The four deceased victims, including JoAnne Kearns of Tampa, Florida; Frank DeLucia of Durham, North Carolina; Tina Hammond and her daughter, Victoria Hammond, of East Patchogue, New York, were discovered in the back of the home in the den and DeLucia dead from a self-inflicted gunshot wound to the chest in the front yard. DeLucia is reported to have shot each of the four victims multiple times, according to police.

"Forty-one years. That was probably one of the most horrific scenes I have ever seen." — Nassau County Police Commissioner Patrick Ryder

Residents are being urged by police to report any suspicious behavior by their neighbors following reports that DeLucia's neighbors claimed the gunman had previously stated, "If you hear gunshots, do not contact the police."

As a community, we are aware of things happening around us. We have witnessed things and heard things. If we remain silent, the consequences can be dire, as we experienced yesterday. The community discussed the distress of the shooter who refused to leave his home after his mother passed away. In the past, the community advised against calling the police if you hear gunfire, as it would be too late.

Law enforcement officials may have been able to respond to the residence sooner if the information he added was not "disturbing."

If DeLucia's concerning behavior had been reported to authorities, it may have been illegal for him to possess his legally purchased shotgun.

Fitzpatrick stated that while it's uncertain if the incident could have been prevented, it's possible that it could have been avoided.

In 2022, police received one prior call to DeLucia's house for a welfare check, but no further action was taken due to her behavior at the time.

Mary Macaluso, a local realtor, informed Newsday that she was scheduled to meet with relatives at the property to discuss selling the home following the death of its owner and family matriarch.

She revealed to the paper that the kids were present at the funeral and requested her to inspect the house. It is reported that one of the siblings had requested the meeting while other relatives from Florida were in town for the funeral.

Planet Chronicle' Michael Ruiz and Lorraine Taylor contributed to this report.