The incident happened in quiet, suburban Orange County neighborhood on Sunday, Jan. 26 at about 8 a.m. at 1751 Route 300 in Chadwick Lake Park in the Town of Newburgh.
It's unclear if the victims were targeted, but officials say there is no threat to the public.
A person of interest is being interviewed by police.
Those killed were a man and woman in their 20s and a 9-year-old boy, police said.
The person injured was a 3-year-old boy who was hospitalized with serious injuries. Police said they believe they were all family members.
Further details, including the identities of those involved, have not yet been released.
The investigation is being conducted cooperatively by the Town of Newburgh Police Department, the New York State Police and the Orange County District Attorney’s Office.
This continues to be a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice Pleasantville and receive free news updates.