The U.S. Coast Guard has suspended the search for two people missing from a plane that crashed in the water off East Hampton on Long Island on Sunday, due to "rapidly deteriorating sea conditions."

The plane, a Piper Navajo PA31, was carrying Hamptons builder Ben Krupinski, 70; his wife Bonnie Krupinski, also 70; their grandson, William Maerov, 22; and pilot Jon Dollard, 47. It crashed around 2:50 p.m., about a mile from Indian Wells Beach in Amagansett. The cause of the crash is not known, but there were reportedly thunderstorms in the area at the time. Two bodies that were recovered from the plane have not yet been identified.

Lt. Alaina Fagan told 27 East, "We are confident based on our search efforts that we've looked extensively at the debris area and where it had traveled. We are confident that if the missing people were on the surface of the water that we would have found them."

The NY Times reports, "Two state troopers were belting their A.T.V.s to a trailer after having finished a patrol along the beach. One trooper said they had recovered some personal effects, believed to be from the plane, that had washed ashore."

Ben Krupinski, once called an "ace East Hampton pilot and Contractor to the Stars" by the NY Times, was known for developing high-end Hamptons homes of Billy Joel, Martha Stewart, and other wealthy denizens. He and Bonnie Krupinski were known for their three Hamptons restaurants, including 1770 House, and their philanthropy around the community. Bonnie's family, the Bistrians, is a prominent land owner in East Hampton.

We are heartbroken to announce the tragic loss of Ben & Bonnie, their grandson Will, and our colleague Jon, on June 2, 2018. The Krupinski, Bistrian, Maerov and Dollard families are grateful for the sincere outpouring of support from so many who knew and loved them. We extend our deep appreciation to the U.S. Coast Guard and other emergency responders on land, sea and air including the East Hampton Town Police Department, NY and scores of others. A memorial service will be announced in coming weeks. In honor of Ben & Bonnie, with whom we have been fortunate to work as members of their extended family, we continue their commitment to delivering excellence in service to all of you in the community. Ben Krupinski Builder The 1770 House Cittanuova East Hampton Point East Hampton Golf Club ... 📷: (L) Ben & Bonnie by @easthamptonstar @godfreypix (R) Will by @patrickmcmullan ... @uscg @bkbuilder @1770house @cittanuovaeh @easthamptonpoint #easthamptongolfclub #hamptons

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Joel said, “I’m shocked and saddened to hear of the death of Ben and Bonnie Krupinski. Ben undertook to get my East Hampton house project completed in the 1980s when the construction progress had been stalled due to bad management. He was always a gentleman and a fair person to deal with. I liked him personally very much, as well. Ben and Bonnie were always quietly doing good things for the community. They will be greatly missed in this part of Long Island."

East Hampton Supervisor Peter Van Scoyoc told WCBS 2, "There’s just a huge hole in the heart of this town right now," noting that the Krupinskis "quietly gave millions of dollars to various charitable causes, to people who were in need. People with medical issues. They arranged flights and medical services for locals. They did not to draw attention to themselves but because they loved the community that they lived in."