Inez Carmaneesh Mon Lambert, 24, from Portland, Oregon, is charged with seven counts each of serious sexual assault, first-degree sex abuse and using a child in the display of sexually-explicit conduct.
The day-care provider, who works at an LA Fitness, was arrested this morning.
Her boyfriend, Corey H. McAdoo, 31, was arrested by the Naval Criminal Investigative Service in Afghanistan where he is serving with the U.S. Marine Corps.
He will be flown back to the U.S. later this month to face charges of possession of child pornography.
An affidavit filed in Multnomah County Circuit Court claims that a friend of Lambert reported the abuse after discovering emails she had left while borrowing her laptop.
It claims the emails contained videos of the sexual abuse.
Portland child abuse detective John Russell interviewed Lambert, and she admitted recording the abuse at her home and sending the footage to her boyfriend 'for his sexual pleasure', according to the affidavit.
Lieutenant Kelli Sheffer, a spokesman for Portland police, told www.oregonlive.com: 'Detectives are concerned about the possibility of additional victims outside of her employment.
'Anyone who may have contracted or paid Lambert for private child care and has concerns is asked to contact police.'
Investigators do not believe the abuse took place at the fitness centre.
