Police say they recovered the taser and two cell phones in the suspect's truck. Officers say the phones belong to two women who police say he raped.
Fresno police say Ramirez showed his victims a badge and then pulled out weapons to make them go along with his plans.
Chief Jerry Dyer said, "In each of the rape cases, Ramirez either utilized a handgun or a taser in order to instill fear into the victims so that they would either get into his vehicle or he would prevent them from escaping from his vehicle."
Investigators say many of his victims were prostitutes, but not all them. Police say Ramirez targeted African American women in their late teens or early twenties.
Thursday on Parkway Drive, one woman said she's been concerned about who he was singling out, but eliminating the risks and dangers on the street is nearly impossible.
"It's not a game, but you put yourself in the game when you are out here you're in the game," said Nykyia Lowe. "It's like a chess board game. It's either you are going to be the last one standing or they."
Officers say the victims were taken from different areas in Fresno, to remote locations in Fresno County. Police say the women were assaulted, and some were even left in the fields where they were raped.
Police were able to identify the suspect, and track him down after his 2012 black Chevy Silverado was captured by a video policing camera.
"We clearly have that vehicle on that camera," said Chief Dyer. "In fact, we know that based on the time frame and the area that the suspect was perhaps driving with the victim in the vehicle at that time enroute to a location for that sexual assault."
Investigators say there's another male accomplice who also was involved in two of the sexual assaults. He has not been identified or found. Officers also believe there are as many as 4 additional victims who haven't come forward yet.
Ramirez has no other prior criminal history. He will likely be in jail for a while now. He's being held on 15 felony counts.