A Milwaukee man was sentenced to nearly 22 years in prison for the sex trafficking of a 15-year-old Wisconsin girl, federal authorities said.

According to the Chicago Tribune, Dajuan Key, 32, received the maximum sentence allowed under federal sentencing guidelines.

Dajuan Key, 32, in a photo from earlier incarceration in Wisconsin, was sentenced Wedneday, Nov. 9, 2016, to nearly 22 years in prison for forcing a 15-year-old girl from Madison, Wisconsin, into prostitution in the Chicago suburbs. Key is from Chicago but had most recently lived in Milwaukee. (Wisconsin Deparment of Correctio /)

32 year-old Dajuan Key, was sentenced Wedneday, Nov. 9, 2016, to nearly 22 years in prison for forcing a 15-year-old girl from Madison, Wisconsin, into prostitution in the Chicago suburbs.(Wisconsin Department of Corrections)

Prosecutors said Key met the teen through an ad she posted to backpage.

com, a site for classified ads. After meeting her in a Madison, Wisc. apartment, Key forced her into prostitution in the Chicago suburbs in September 2013.

Despite promises of letting the girl keep the money she earned to pay for a bus ticket home, Key repeatedly took the money and forced her to continue prostituting herself. According to the Tribune, the girl was rescued later that month by local police after she fled to a McDonald’s and called police. Authorities arrested Key after finding evidence corroborating her claims on Key’s tablet and GPS devices.

According to Margaret Wolski of New Name Ministries, a national non-profit organization which aids victims of human trafficking in the U.S., thousands of youth under age 18 are targeted annually.

“Every year, 15,000 to 24,000 people in Chicago land become victims of human trafficking,” Wolski told the Tribune. “Of these, 35 to 40 percent are under age 18. Most are trafficked for sex or pornography. The average age of entry into this form of slavery is 12 to 14.”