Story highlights Jorge Juan Castro, an associate pastor, is being held in lieu of $2 million bail

The alleged abuse began shortly after he arrived from Argentina

Castro allegedly raped more than 20 undocumented immigrants

He allegedly threatened to have them deported if they told

It would not be surprising for an associate pastor to pray with his parishioners.

But Jorge Juan Castro wound up preying on them instead, the Los Angeles County Sheriff's Department said Friday. He is accused of raping more than 20 women, many of whom are Spanish-speaking, undocumented immigrants.

The alleged abuse began in October 2004, shortly after Castro took a job as associate pastor at Las Buenas Nuevas Church in Norwalk, and continued until September 2012, the department said in a news release.

Castro was arrested last Friday at his home in Norwalk and was being held in Los Angeles County Jail in lieu of $2 million bail.

The allegations came to light when the women, ages 18 to 39, implicated Castro to a third party who then told detectives, authorities said.

The alleged incidents began in October 2004 and continued until September 2012.

During that time, Castro was working as an associate pastor and counselor at Las Buenas Nuevas Church in Norwalk, the department said.

"The suspect allegedly preyed upon the victims' vulnerability," the news release said. "He did this by invoking fear by threatening to tell the victims if they reported him he would have the victims deported, while additionally threatening to expose the victims to public embarrassment and ridicule."

Castro was booked on an arrest warrant listing six felony charges of rape, oral copulation and penetration by a foreign object, authorities said.

Detectives from the county's Special Victims Bureau were asking for help from the public in identifying any other possible victims.