CHICAGO (CBS) — A Chicago Public Schools teacher was charged Thursday with sexually assaulting a teenage girl over a four-month period this year at a South Side school.

Anthony Frontera, 53, was arrested about 3:45 p.m. Wednesday in the 100 block of Douglas Avenue in Elgin, according to Chicago Police.

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Police said Frontera sexually assaulted a 16-year-old girl multiple times between Jan. 1 and May 11. He was charged with two counts of felony criminal sexual assault of a victim between 13 and 17 years old.

Anthony Frontera (Source: Chicago Police)

A police source said the assault happened at the Chicago Military Academy at Bronzeville, 3519 S. Giles Ave.

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Frontera, of the Belmont Heights neighborhood, was listed in Chicago Public Schools employee position roster published in March, and a website for the Chicago Military Academy lists Frontera as a physics teacher.

CPS did not respond to a request for information Thursday night.

Frontera was expected to appear in court Friday.

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(Source: Sun-Times Media Wire © Chicago Sun-Times 2017. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)