Campbell said Nevins, originally from Oceanside in Nassau County, N.Y., died of hyperthermia within an hour to 90 minutes. His death was ruled accidental.
According to police, Nevins and three other residents of the sprawling community had been taken in a Kia Sedona minivan to Sesame Place that morning with two counselors. When the van returned at about noon, one counselor was dropped off with his two clients, while the driver drove her charges to Woodlands, a cluster of small buildings devoted to people with varying degrees of intellectual disability and significant behavioral problems.
The driver then parked the van in its usual spot and turned in the keys. She completed her shift at 3 p.m. It wasn't until an hour later, when a nurse went in search of Nevins to give him his medication, that staff discovered he was missing, police said.
For more than an hour they looked for Nevins, who could walk but was not verbal, starting with all the nearby buildings before turning to the vehicles.
Nevins was discovered dead in the back of the maroon van in which he had traveled to Sesame Place, lying down in a backseat.
It was not clear whether the van locked from the inside.
The young man was a triplet, and a brother was also a client at Woods Services. His parents, Diane and William Nevins of Oceanside, removed their second son from the facility late Saturday.
William Nevins is a celebrated retired New York police lieutenant who broke a string of high-profile cases, including the Wendy's massacre a decade ago.
The family declined to comment Tuesday.
"William Nevins is a brilliant, great detective. He and his wife are incredible people," said Nevins' onetime attorney, Harry Kutner Jr. "I can't believe it. It's a terrible tragedy for any family."
