Gunfire detected in Roosevelt Monday night was followed minutes later by the discovery of a gunshot victim in nearby Freeport, Nassau police said.

The male shooting victim collapsed at Babylon Turnpike and Woodside Avenue in Freeport before being discovered at about 7:48 p.m., police said, and investigators were trying to determine whether he was wounded about a block away on Jefferson Avenue in Roosevelt.

That was where ShotSpotter, a gunfire detection system, registered gunfire at about 7:44 p.m., alerting the First Precinct, police said.

The victim was taken to a hospital, police said. His condition was not immediately available.

Officers with flashlights could be seen examining the sidewalk, front yards and the curbside on Jefferson Avenue near Babylon Turnpike.

One resident on the street said she heard what sounded like gunfire while she was watching television and thought it was some Halloween revelers shooting off.

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“It sounded like about four shots,” said the resident, who did not want to be identified, “but when I looked out the window, I didn’t see anything, just a car driving away.”

At one corner house on Jefferson Avenue and Babylon Turnpike, five young males were cuffed and sitting on the porch as some officers stood nearby and others went in the house.

One officer could be seen wearing a bullet-resistant vest with the words “Special Investigations Squad,” a Nassau police team that investigates gangs and organized crime.

Freeport police declined to comment.

Other details were not immediately available as the investigation evolved.