OAKLAND — A former Brazilian police officer is scheduled to enter a plea Nov. 20 to 17 felony charges involving sexual assaults on six women in Oakland and Emeryville from April to last month, authorities said Friday.

Authorities said the suspect, Gleiston Porcino De Andrade, 38, a truck driver from Alameda, has been in the United States 12 years.

Authorities here said he told some of his victims he was a police officer and in one instance produced a phony gold badge.

Besides the six cases De Andrade is charged with, police believe he attacked more women and are trying to locate them. De Andrade has refused to talk to police about the attacks.

The known victims in the series of attacks, which began April 9 and ended when he was arrested Oct. 26 by an Emeryville police officer who saw him assaulting a victim in a truck, range in age from 15 to 25.