Prosecutors said it's something that went on for months.
The DuPage County State's Attorney identified the man as Ramon Ochoa Garcia. He now faces charges of unauthorized video recording of a person under 18 and unauthorized video recording without consent.
Investigators say Garcia put a small pen camera into a vent to record people in the women's bathroom at World Mission Society Church in Bloomingdale, located off of South Bloomingdale Drive.
The crimes started as early as August 1, police said.
A pastor at the church later found the pen and reported it to police.
Prosecutors believe there are at least 24 victims who were recorded, including two young girls.
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On Thursday, a judge denied prosecutors' request to detain Garcia before his trial, despite their argument that he was a flight risk since he allegedly lives in a van.
The church told ABC7 they have no comment on the matter as police continue to investigate.
Garcia could face additional charges as more potential victims are identified in the case.