A man believed to have been trapped by a fast-moving brush fire in Ventura County was found dead near the Santa Clara River on Wednesday, officials said.

The Olivas fire was first reported about 8 a.m. Wednesday and burned near the Santa Clara River bottom, an area frequented by homeless individuals in the area, according to a statement from the Ventura County Sheriff’s Office.

After the 11-acre blaze was contained, deputies received a call about a man’s body found in the area where the fire burned. The man has not yet been identified.

At the time of the fire, staff from the Sheriff’s Office Homeless Liaison Unit had been in the area, urging people to leave.

It took firefighters about three hours to contain the blaze, according to the California Department of Forestry and Fire Protection.

The cause of the fire remains under investigation.