Barry Freundel, 63, may have recorded as many as 150 women in the changing area at his orthodox synagogue in Washington DC.
The women were disrobing for the ritual Jewish bath, known as a mikvah.
Rabbi Mendel Epstein faces charges of conspiracy to commit kidnapping and attempted kidnapping in New Jersey.
Prosecutors allege Rabbi Epstein's team used tools including cattle prods to force husbands to agree to divorce.
Defence lawyers said he was a "champion of women's rights" and disputed the charges.
Under Orthodox Jewish belief, a husband must grant permission for a divorce. This comes in the form of a document known as a get.