By Phil Corso

Story last updated 2.22.16, 12:30 p.m.

Police are combing through the region where Port Jefferson Harbor and Setauket Harbor meet near Poquott after a small plane crashed there late Saturday night, authorities said.

The small plane, which cops said was a Piper PA-28 carrying four people, went down shortly after 11 p.m. near the vicinity of 108 Van Brunt Manor Rd., Poquott Mayor Dee Parrish said. An extensive response from emergency personnel followed, during which three people were recovered from the water — but one remained missing, and that search was ongoing through the beginning of this week, officials said.

Police said on Sunday that a student pilot, 25-year-old Bronx resident Austricio Ramirez was flying the plane when the problems arose and turned the controls over to his instructor, 36-year-old Queens resident Nelson Gomez, who landed the plane in the harbor.

All the passengers in the four-seater plane were able to exit into the water, after which Ramirez, Nelson and passenger Wady Perez, a 25-year-old from Queens, were rescued by police.

But Suffolk County Police Commissioner Tim Sini said the search and rescue operation remained in effect for one missing person, who was identified as 23-year-old Queens resident Gerson Salmon-Negron, with assistance from the U.S. Coast Guard.

“We’re going to do everything we can to find that individual,” he said.

The three people pulled from the water were being treated at Stony Brook University Hospital, officials said. They have since been released.

Peter Stubberfield of Poquott said he and his wife heard the plane flying immediately above his house off the harbor Saturday night immediately followed by the sound of emergency vehicles.

“Within minutes of hearing the plane, there were about 15 to 20 emergency vehicles right in front of our private drive,” he said. “There were two helicopters flying around continually, so we assumed something was going on in the water.”

Margo Arceri, who lives on the Strongs Neck side of the water where the plane crashed, said she and her neighbors jumped into action as soon as they noticed emergency vehicles making their way into the small North Shore community. Upon stepping outside Saturday night, Arceri said she watched emergency personnel pull survivors out of the water, wrap them in blankets and remove them to the nearby hospital.

As the incident unfolded, Arceri said everyone living along the shoreline did something to help, whether that meant picking up a telephone, making way for emergency responders, or even offering up their personal kayaks for rescuers to use to lift the survivors out to safety.

“Where this occurred, there are only a few homes, but instantly, the neighbors pulled together,” she said. “They say, ‘it takes a village,’ and these neighbors showed a real sense of community. We all pulled together immediately. I just wish it had a happier ending.”

One eyewitness who did not want to be named said she called the police Saturday night after watching the plane fly over her Poquott home and into the water. Seconds after hitting the water, the resident said she heard the survivors in the water yelling to each other.

“It sounded like they were talking to each other — not calling out for assistance. I yelled to them to ask if they needed help, but they didn’t hear me at all,” she said. “Within seconds, I saw a large helicopter overhead.”

Police arrived soon after, the woman said, and she and her husband then offered up their three personal kayaks to rescuers, who used the boats to retrieve the survivors.

“I just wish I had put the phone down and run down to the beach,” the witness said. “I just watched. I saw the lights on the plane go out. I’m having a really horrible time with this whole thing.”

A spokesman with the Federal Aviation Administration said Sunday that the plane was en route to Republic Airport in Farmingdale, after taking off from Fitchburg, Mass., but the pilot was reporting engine issues before attempting a forced landing.

Both the FAA and National Transportation Safety Board were at the scene of the crash from Saturday night into the beginning of this week to help with the search efforts, authorities said. Also helping the Suffolk County Police Department and the Coast Guard were local fire departments and the town harbormaster.