Eighteen men have been arrested in Minnehaha County on charges of hiring or attempting to hire a person to have sex. Solicitation is a class one misdemeanor in South Dakota. Two of the 18, Neal Castle and Nickolaus McCracken, were arrested on felony charges for statutory rape and solicitation of a minor.

Authorities believe Castle and McCracken not only solicited, but also had sex with minor teenage girls who were being used in a 2009 sex trafficking bust in Tea.

Authorities say the website Backpage.com is the common thread between the latest 18 arrests. An on-going federal investigation into sex trafficking in South Dakota tipped them off when someone thought a female in an ad on Backpages.com looked underage.

Minnehaha County State's Attorney Aaron McGowan says there have been more prostitution related arrests lately stemming from cell phone calls and websites with sexually themed classified ads.