Mystery Surrounds Deaths of New Jersey Hospital Executive, Wife, in Arson Fire

— -- Investigators in New Jersey still haven't identified the cause of death for a hospital executive and his wife who died Sept. 28 after a fire was intentionally set inside their home, authorities said.

Audio from a neighbor’s 911 call released this week reflects the confusion surrounding the deaths of John Sheridan Jr., 72, and his wife Joyce, 69.

A neighbor in Montgomery Township, Somerset County, reported noises, “like somebody tapped on the window.” Investigators believe that those sounds were not someone trying to escape but were caused by the fire.

The husband and wife, who were married for 47 years, were found unconscious by firefighters in the home’s second-floor master bedroom. Joyce was a retired schoolteacher, while John was the president and CEO of Camden-based Cooper University Health Care, one of the state’s large hospitals.

While the fire was ruled intentional, authorities told ABC News they’re still waiting for lab results, hoping to understand how the Sheridans died.

The investigation is “very complex,” an investigator said.

More than 800 mourners – including Gov. Chris Christie, a family friend – attended an Oct. 7 memorial service for the couple. Camden County Assemblyman Lou Greenwald has expressed surprise and sadness about their deaths.

“We don’t know what happened. All I knew is we lost a wonderful public servant,” Greenwald said.

The couple’s four sons and three grandchildren remain devastated by the situation.

“The death of our parents has left a hole in our hearts and our family that can never be filled,” the statement reads. “We cannot fathom, much less explain, the circumstances of their passing.”