TRENTON - A teacher at New Jersey State Prison in Trenton had sex with an inmate more than 20 times and twice became pregnant during the sexual relationship, according to Mercer County Prosecutor's Office.

Chong-Hwa Chang (Facebook photo)

Chong-Hwa Chang, 42 of Delran, was arrested Jan. 29 and charged with one count of sexual assault after the state Department of Corrections launched an investigation into her relationship with an inmate, prosecutors said.

Chang was a teacher at the correctional institute when she began the sexual relationship with an inmate, prosecutors said. The state Department of Corrections notified Mercer County Prosecutor's Office before searching Chang's home and car.

In her home they found a journal, Chang used to detail her relationship with the inmate. In it, she admitted that she had sex with the inmate and had gotten pregnant twice, prosecutors said.

They also found sexually explicit photos of Chang during their search. After her arrest in January, Chang admitted to having sex with the inmate at least 20 times. The timeline for the alleged sexual relationship was not immediately clear.

Chang earned $74,743 from the Department of Corrections in 2015, according to state payroll data. She has been working as a teacher for the department for nine years, according to her LinkedIn profile.

At a bail hearing Thursday morning, a judge reduced Chang's bail from $75,000 to $50,000.

The name of the inmate was not released because he was a victim in a sexual assault case.

Anna Merriman may be reached at amerriman@njadvancemedia.com. Follow her on Twitter @anna_merriman Find The Times of Trenton on Facebook.