CLARKSBURG, W.Va. -- A Massachusetts woman accused of posing as a teenage boy to prey on a West Virginia girl pleaded guilty to one federal charge Wednesday and could face up to 30 years in prison when sentenced. Carissa Hads, 25, of Quincy, also could be fined as much as $250,000 when sentenced on the single count of traveling across state lines with the intention of having sex with a minor. She's in custody and appeared before U.S. Magistrate John Kaull in Clarksburg to enter her plea. Investigators say Hads pretended to be an 18-year-old named James Puryear Wilson on the social networking site MySpace and started a relationship with the Lewis County victim in 2010. The two communicated for more than a year before their first in-person meeting. A State Police investigator said Hads wore colored contact lenses and a back brace to cover her chest, and that she visited the 15-year-old girl at least three times, once at a Pittsburgh motel in December 2011. The victim also took naked photos of herself and texted them to Hads on a cellphone that Hads provided, authorities say. The criminal complaint said Hads then flew to West Virginia in February, and had a sexual encounter with the girl at her Lewis County home. Hads did not undress during that encounter.Another West Virginia teen became suspicious of Hads' true identity, the State Police investigator said, and alerted authorities in March after Hads threatened her. Hads was arrested in May at the Pittsburgh International Airport. Under the plea agreement, she also agreed to surrender her computer and other electronic equipment seized from her home.