A 63-year-old Long Island woman was found dead in her backyard pool yesterday afternoon, and her son is now in police custody for her murder.

Denis D. Cullen Jr., 23, who was charged with second-degree murder, lives with his parents at their home on White Hill Road in Cold Spring Harbor, a wealthy enclave on the North Shore. Police were asked to make a wellness check on Elizabeth Cullen—someone called saying she had drowned— and found her in the pool just before 4 p.m.

Suffolk County Police Commissioner Timothy Sini said, "While we were processing the scene, the suspect returned to the home and we placed him under arrest."

The investigation is continuing. Cullen is to be arraigned today.