Undercover police officers posing as men seeking sex arrested four women who had offered their services online, police said.Greenwood police set up the undercover sting on Friday after contacting several women advertising sensual massages on the popular Web site, Craigslist, 6News' Ben Morriston reported.Each woman agreed to meet in a Greenwood motel room and charged between $80 to $200 to perform sexual acts, said Assistant Chief David Mertz."Our undercover officers were able to make prostitution arrests upon the services that these individuals had agreed to perform," he said.Mertz said prostitution is a growing problem in Greenwood and in other parts of the state. He said the Internet and the economic downturn have given new life to the world's oldest profession."This is an age-old problem that's occured out there, but the economy could very well play a factor in that," he said.Some Greenwood residents said that Web sites, like Craigslist, should better patrol the offers being made on their sites."I think it's good [the police] did that," said resident Helen Birch. "I think Craigslist needs to be more strict who they let on their site. I'm sure they knew about it."Before entering Craigslist personal ads, visitors agree to flag any posts that are illegal and also release Craigslist from "liability that may arise from the use of this site."All of the women in Friday's sting -- TeAndra Moore, Belinda Boyd, Amy Hargis and Kelsey Killebrew -- were arrested and preliminarily charged with prostitution.Police said Killebrew, who was carrying a pistol in her purse, will have her gun permit revoked. Killebrew contacted 6News on Friday to say that the gun was in her vehicle, not in her purse.Another woman was preliminarily charged with possessing marijuana.All four were released Friday after posting bond.