A Mississippi man has been sentenced to more than 30 years in prison for drugging children and then trafficking them for sex.

News outlets report 37-year-old Willie Charles Blackmon Jr. was sentenced Monday after being convicted in November of sex trafficking minors and promoting a prostitution business. He was also ordered to register as a sex offender and sentenced to a lifetime of supervised released.

Prosecutors say an investigation into the prostitution ring led by Blackmon started in 2014. Authorities say he bought a runaway minor for $500 and then recruited other runaways for prostitution. U.S. Attorney Mike Hurst says Blackmon would rent hotel rooms in Jackson and Vicksburg where the children would be prostituted. Prosecutors say Blackmon also harmed the children if they refused to perform sex acts.