The world's oldest profession has gone high-tech.

Authorities say John Calvin Guerra, known as "G," and three accomplices ran a prostitution ring using laptops, prepaid credit cards, cell phones and digital cameras to post photos of girls looking for "dates" on Craigslist's erotic-services section.

Guerra, of Tackawanna Street near John, in Frankford; Edinelson "Eddie" Mendez, 20, of Tioga Street near 9th, North Philadelphia; and two others, one now in a Maryland prison and the other from Wilmington, were charged yesterday with a variety of counts related to the ring.

The state grand-jury report said the prostitutes, one of whom was only 17, often worked out of rooms at hotels, including two on Roosevelt Boulevard.

The women allegedly were controlled by Guerra and the others by being punched in the ribs.

The women sometimes were paid in drugs, including crack cocaine, the grand jury said.

One woman testified that she received $20 worth of crack cocaine for each "date."

Authorities said the ring began operating in July 2008 and came to light Feb. 16, 2009, after one woman was arrested on another charge at the Ramada Inn on Roosevelt Boulevard.

- Gloria Campisi