A 28-year-old Twin Cities man branded as a career criminal who “bought and sold human beings for his own personal gain” in sex trafficking has been sentenced to 15 years in prison.

The sentence of Napoleon Long, of Fridley, in federal court in St. Paul includes another 15 years of court supervision upon release. Long pleaded guilty in July, admitting that he traveled with a 17-year-old girl from Minnesota to Colorado Springs so she could have sex for money.

Prosecutors say that Long set up his operations in Fridley, dispatching girls across the Twin Cities and Midwest.

With the help of another man, investigators said, Long trafficked as many as 40 girls and young women for sex.

“The offenses the defendant committed were predatory, exploitive, sadistic, demeaning and physically dangerous to the victims,” Assistant U.S. Attorney David Steinkamp wrote, arguing for a prison term of more than 19 years.

The girls and women “received nothing but sustenance as he reaped the profit from their acts,” he noted.

The prosecution said that Long spent his adult life committing increasingly serious crimes, starting at age 18, when he was convicted of possessing marijuana.

Long’s defense, in asking for a prison term of less than 13 years, noted that he had not been accused previously of a sex-related offense.

The prostitution ring was exposed after two teenage girls told police a man had sex with them and tried to lure them into prostitution.

Long allegedly used the Backpage.com website to advertise the girls and women for sex.

A second man, Kevin Wadell Moffitt, also of Fridley, pleaded guilty to felony criminal sexual conduct in Anoka County District Court and was sentenced to nine years, seven months.