A Michigan sex offender who had already spent several years in prison for infecting his sexual partners with HIV has now been arrested for allegedly transmitting the disease to a 15-year-old boy he raped, authorities said.

John Dushan Cole, 55, was taken into custody on a string of charges last week after the teen’s family alerted the Genesee County Sheriff’s Office last month.

“He is one of the most vile [predators] that I’ve seen,” Sheriff Christopher Swanson said. “His grooming tactics were some of the best that I’ve seen, in the worst way.”

Cole, who was previously known as Johnny Peters, allegedly started grooming his alleged victim in December of last year after making friends with one of the boy’s relatives at a community event.

Text messages uncovered from Cole’s phone show he had been exchanging daily messages with the boy — including some where he offered the alleged victim wads of cash.

He is accused of sexually assaulting the boy for the first time in February when he was given permission by family members to take him to a basketball game, the sheriff said.

The next month, Cole allegedly attacked the teen again at a bowling alley birthday party.

The teen’s family took him into the sheriff’s office in April to report the alleged crimes. Investigators say the boy had contracted HIV.

During the probe, authorities realized Cole had previously been jailed for sexual offenses — but he had recently changed his name from Johnny Peters.

His first brush with the law came in 1987 when he was convicted of fourth-degree criminal sexual conduct. It wasn’t immediately clear if he served time in prison.

Then in 2013, Cole was sentenced to seven years in prison for knowingly infecting adult sexual partners with HIV. He changed his name at point after being released, the sheriff said.

In the wake of his recent arrest, investigators are now trying to determine if he has any other recent alleged victims.

Cole remains locked up on 12 felony charges, including criminal sexual conduct, accosting a child for immoral purposes and knowingly engaging in intercourse with the intent to infect an uninformed partner with HIV.