34-year-old Randolph Smith has been arrested for knowingly spreading the HIV virus to numerous women he met on various dating websites, WUSA 9 reports. During the 22-month investigation, detectives contacted several of the victims and eventually obtained enough evidence through search and seizure warrants to support a case against Smith. Medical records were also reportedly reviewed to confirm key statements.

Smith met several of his victims on Backpage and Bumble, according to The Frederick News-Post. The investigation into his crimes began in July 2017, when police received a tip from a woman who tested positive for HIV and she believed Smith transferred the virus to her. Three more victims were identified over the next several months, the report states.

Bumble is a social and dating app that doesn’t subscribe to gender norms and makes it “acceptable for women to make the first move,” according to the website. Back in January, the company tapped tennis champ Serena Williams for its full 30-second Super Bowl spot.

Backpage.com was a classified advertising website frequently used for selling sex. The site was the subject of an FBI investigation over accusations that users were encouraged to post ads related to prostitution and human trafficking. The site was shut down last year and all data was reportedly seized by law enforcement.

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Smith was taken into custody on Monday. A Frederick County grand jury has indicted him on four counts each of first-degree assault, reckless endangerment and knowingly transferring HIV to another person.

One Facebook user reacted to the report by noting “The women share the responsibility for not protecting themselves.”

Another said: “Ladies, keep your legs closed to strangers. You never know.”

A third added: “Not just strangers, it is the ppl you know that will give it to you cause you think you trust them cause you know them.”

User Carol Edmonds said: “He is responsible for the effects of transmission of this DEADLY illness. It IS deadly if they don’t get tested and begin treatment for it. Once it’s under control, his victims will require lifetime monitoring!!”

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Investigators are asking anyone who had a sexual relationship with Smith around or after July of 2017 to contact them via email at FPDcrimetip@frederickmdpolice.org.

As of 2018, 26 states have implemented HIV-specific criminal exposure laws. Knowingly infecting others sexually, by way of reckless endangerment or attempted murder, can be used to criminalize behaviors, according to the CDC.