FALLS CHURCH, Va. (WUSA9) -- The names of the four officers involved in the death of a disabled man while in police custody have been released.

All four of the officers are on administrative leave as police continue their investigation into the death of Paul Gianelos, which occurred while he was on an outing with the organization caring for him.

The 45-year-old's family says Gianelos was profoundly autistic and did not speak. He lived in St. John's Community Services in Annandale.

When the group leader realized Gianelos wandered away during an outing at Round Tree Park, they called 911.

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Police chief Edwin Roessler says the officer who spotted Gianelos is a 25-year-veteran with crisis intervention training.

A second officer arrived, but when they tried to get Gianelos in their vehicle, there was a struggle.

"Don't know why [there was a struggle]. Part of the investigation," Roessler said.

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Two other officers arrived before Gianelos arrived at Inova Fairfax Hospital, where he was pronounced deceased.

Lucy Beadnell with The ARC says the officers should have been given information about Gianelos, and how to deal with him, before they arrived. She also says a Project Lifesaver bracelet with a tracking element could have helped locate him in the first place.