Meng Linggong, 69, of San Jose, was reported missing around 11:20 p.m. Monday. He suffered from dementia and his family was concerned for his well-being.
After police found Linggong's cellphone around 2:40 a.m. Tuesday in Alviso Marina County Park, search-and-rescue units responded to assist, and a tracking dog was deployed.
Linggong's body was found around 4:30 p.m. Tuesday in a marshy area near the Alviso Marina, police said.
The Santa Clara County medical examiner's office has taken custody of his body and will conduct an autopsy to determine the cause of death.
Police said there is no indication of foul play.