It happened in the town of Ceres in Stanislaus County. Neighbors dialed 911 after hearing screams for help.
Police arrived to find a man's legs sticking out of a small drain.
Authorities thought he was intoxicated.
The man said he ended up in the drain after being mugged by gang members. He said he didn't tell police about the gang members because he was afraid of gang retaliation.
The incident was under investigation.