defensive when questioned by a surrogate's lawyer. >> reporter: officials say carla chambers, hilary neimanesa erickson preyed on unwitting surrogates for at least four years, selling unborn babies to the highest bidder. here's how it worked. chambers arranged for surrogates to be impregnated with donated embryos. neiman preyed on desperate parents. erikson falsified documents in san diego superior court to close the transaction. fbi special agent in charge keith slotter. >> trafficking in human life without having a parent ahead of time is really, i think, quite troubling. it crosses that line, i think, from the surrogate adoption-type world to simply dealing with children as commodities. >> reporter: officials say they pocketed millions from their scheme which produced about a dozen babies. authorities say there could be more. all three women who ran the ring refused cnn's repeated requests for comment and they pleaded guilty to charges of wire fraud and conspiracy. they face a maximum of five years in prison and a $250,000 fine. law enforcement officials say in exchange for their guilty

defensive when questioned by a surrogate's lawyer. >> reporter: officials say carla chambers, hilary neimanickson preyed on unwitting surrogates for at least four years, selling unborn babies to the highest bidder. here's how it worked. chambers arranged for surrogates to be impregnated with donated embryos. neiman preyed on desperate parents. erikson falsified documents in san diego superior court to close the transaction. fbi special agent in charge keith slotter. >> trafficking in human life without having a parent ahead of time is really, i think, quite troubling. it crosses that line, i think, from the surrogate adoption-type world to simply dealing with children as commodities. >> reporter: officials say they pocketed millions from their scheme which produced about a dozen babies. authorities say there could be more. all three women who ran the ring refused cnn's repeated requests for comment and they pleaded guilty to charges of wire fraud and conspiracy. they face a maximum of five years in prison and a $250,000 fine. law enforcement officials say in exchange for their guilty pleas,