DETROIT (AP) — A federal jury on Thursday convicted a 70-year-old Detroit man on drug and human trafficking charges.

The U.S. Attorney’s Office in Detroit said in a release that Richard Jackson was found guilty of sex trafficking using force and coercion, drug distribution and maintaining drug premises.

Authorities say the investigation began after a 911 call in 2016 from a woman pleading for help. Detroit police officers went to the home and found squalid conditions, signs of intravenous drug use everywhere and a security gate installed at the top of a stairway.

U.S. Attorney Matthew Schneider said in a statement that Jackson “targeted vulnerable women and exploited them for his own profit.” He added that Jackson “manipulated his victims’ drug addictions.”

Sentencing was set for April 16. Jackson faces at least 15 years in prison.