Orange Park police searching for missing endangered man with dementia Denison Mullen was last seen around 7 p.m. Sunday at his home on Sandy Court in Orange Park. Credit: Orange Park Police Published: 11:04 PM EDT July 11, 2021 Updated: 11:07 PM EDT July 11, 2021 ORANGE PARK, Fla. — The Orange Park Police Department is asking for help searching for a missing and endangered man. Police said Denison Mullen was last seen around 7 p.m. Sunday at his home on Sandy Court in Orange Park. He was last known to be wearing a blue shirt and blue pants. Mullen walked away from his home and also suffers from dementia, police said.