A 56-year-old registered sex offender was convicted Tuesday of sexually abusing a young girl and woman in two separate incidents on the 7 train in Queens, prosecutors said.

Paul Kingsley, of Brooklyn, was convicted of multiple sexual abuse charges, harassment and endangering the welfare of a child, according to Queens District Attorney Richard A. Brown. He faces up to two years in prison and indefinite civil commitment for allegedly violating the terms of parole at his June 14 sentencing.

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According to Brown, during the incidents Kingsley "was wearing an ankle-mounted GPS tracking device that was being monitored by state authorities."

Kingsley was designated a sexually violent offender and predicate sex offender and was required to register for life with the New York State Sex Offender Registry in 2001, prosecutors said. He was convicted in both North Carolina and Syracuse, New York for sexually abusing, in both instances, a 9-year-old girl in a library.

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The incidents in Queens, which involved a 13-year-old girl and a 23-year-old woman, occurred within minutes of each other on December 6, 2013 on two different trains.

According to trial testimony, Kingsley was observed by two undercover police officers sexually abusing the 13-year-old on the subway. One of the officers spoke to the girl while the second officer followed Kingsley onto another train. While aboard this train, the officer saw Kingsley sexually abuse the 23-year-old. 

"As such, he has proven himself to once again be a clear and present danger to females of all ages and to society in general,” Brown said.