Prosecutors say a Pennsylvania father and son dispatched prostitutes to New York City, where livery cab drivers helped the women find customers.

Six drivers were awaiting arraignment Monday on promoting-prostitution charges in an unusually broad sex-trafficking case. The Manhattan district attorney's office says the case is expected to include charges against not only the alleged ringleaders and driver-recruiters but also some accused customers.

The father and son from Allentown, Pa., are being held without bail. Vincent George Sr. and Vincent George Jr. pleaded not guilty earlier this month to sex trafficking and other charges.

Prosecutors say the prostitutes grossed as much as $500,000 a year apiece for the men, but the women got only a few dollars a night to buy food and other necessities.