Three people were rescued and one was missing after a small plane went down Saturday night in Long Island Sound.

The four-seater Piper was on its way to MacArthur Airport in Islip when the pilot reported an engine problem, the FAA said.

It went into the water in Setauket Harbor, less than one mile from land, at about 11 p.m. Suffolk cops pulled three people from the water. Their identities and conditions were not immediately known.

The search continued early Sunday for the fourth victim.