A pastor at a Southern California church has been arrested for allegedly sexually abusing at least 20 female members of the church, most of them undocumented immigrants.

Jorge Juan Castro, 53, is an immigrant from Argentina who moved to the Los Angeles area in 2004. He then became an associate and counselor at Las Buenas Nuevas Church in Norwalk, California.

According to LA Times, Castro abused women between the ages of 18 and 39, starting as early as October 2004 to September 2012.

Detectives started investigating Castro after numerous women confided in a third party member of the church, who then informed authorities. Castro was arrested Sept. 13.

Castro allegedly used the victims' vulnerability as illegal immigrants to his advantage and threatened to have them deported if they spoke out about the abuse.

“The suspect allegedly preyed upon the victims’ vulnerability,” the LA County Sheriff's Department said, NBC reports. “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 is being charged with six felony counts of rape, oral copulation and penetration by a foreign object. He is being held on $2 million bail.