A man from Missouri has been accused of filming himself giving unsuspecting partners HIV.

Michael Johnson, 22, allegedly filmed himself having sex with 31 people. Police discovered the sex videos on his laptop, in October last year.

Many of the videos had been made with a secret camera hidden in his dorm room on his campus in Lindenwood University, where he is a student.

His alleged crimes came to light after a man came forward to tell police he had been diagnosed with HIV and gonorrhoea a month after having sex with Johnson, who goes by the name of Tiger Mandingo online.

"On that laptop were 32 videos [of men] engaged in sexual acts with Mr. Johnson," said St. Charles County prosecutor Tim Lohmar.

"It's safe to say that numerous of those videos were taken inside his dorm room; we know that because we recognise the furniture."

He was arrested after the videos were found and prosecutors are currently trying to identify some of the people in the videos. Police have urged people who have had sex with Johnson to come forward, as it is a matter of public health as well as a criminal trial.

Lindenwood University school officials are currently assisting police in trying to identify his victims.

Court records show he lied to some partners who had asked him if he had any sexually transmitted diseases.

Following a five month investigation, Johnson was found to have six social media accounts that he used to meet sex partners.

If Johnson is found guilty of knowingly infecting someone with HIV, he faces a life sentence.

Lindenwood student Jenny Counts told News 4 she was shocked: "I think it's really scary, thinking someone like that is on campus, not thinking about others."