A 76-year-old veteran committed suicide on Sunday in the parking lot of the Northport Veterans Affairs Medical Center on Long Island, where he had been a patient, according to the Suffolk County Police Department. Peter A. Kaisen, of Islip, was pronounced dead after he shot himself outside Building 92, the nursing home at the medical center. The hospital is part of the Veterans Affairs medical system, the nation’s largest integrated health care organization, which has been under scrutiny since 2014, when the department confirmed that numerous patients had died awaiting treatment at a V.A. hospital in Phoenix. Officials there had...