Prosecutors in Missouri are hoping to hear from acquaintances of Michael Johnson, a former student of Lindenwood University, who has been accused of knowingly exposing more than 30 of his sexual partners to HIV.

A police investigation found 32 videos of Johnson engaging in unprotected sex with at least 31 people over a period of 4 months. Police believe none of Johnson's partners, whom he met both online and through school, were aware they were being filmed or that he had HIV, the virus that causes AIDS.

The St. Louis Dispatch reports Johnson, a former member of the Lindenwood wrestling team, was originally arrested and charged with having knowingly spread the virus to one other partner in October 2013. In November, four other partners came forward, resulting in four additional felony charges filed against Johnson.

Last week, investigators found a laptop full of what appear to be Johnson's covertly-filmed sex tapes, dating back to his days as a student.

Johnson, 21, operated under the alter-ego "Tiger Mandingo" for many of his online profiles, notes The Riverfront Times, many of which were saturated with photos of him posing shirtless and flexing.

“It's safe to say that numerous of those videos were taken inside his dorm room; we know that because we recognize the furniture,” Tim Lohmar, the St. Charles County prosecutor, told KMOV.