A former middle school instructional assistant infected with HIV is facing more than 100 felony counts of child sex abuse and other offenses after authorities in Southern Maryland identified at least two dozen victims, according to Charles County court documents and lawyers.

The case against Carlos ­Deangelo Bell, 30, began after a parent noticed sexually explicit text messages on her son’s phone. A police investigation later determined that the child abuse spanned nearly two years until Bell was arrested in late June and that some of the incidents may have taken place in classrooms on public school property.

Bell now faces 119 counts, including charges of assault, child sex abuse, solicitation, attempting to infect at least three victims with HIV, filming children in a sex act, showing obscene imagery to minors and distribution of marijuana. Police have found at least 24 victims, who at the time were in sixth to eighth grade, according to reports from WTOP radio.

Bell began working for Charles County schools in September 2014. He was an instructional assistant at J.P. Ryon Elementary until March 2015, when he joined the staff at Benjamin Stoddert Middle School. While at Stoddert, he also was an indoor track coach at Maurice J. McDonough High until he was put on administrative leave in late December 2016.

Bell appeared in Charles County Circuit Court on Monday afternoon. An attorney for Bell, Jeffrey Griffith, said afterward, “He’s looking forward to his day in court to fight these allegations.” The Charles County state’s attorney, Anthony B. Covington, did not respond to a phone message seeking comment.

When he was arrested on June 30, Bell was charged with three felony counts of producing child pornography. Authorities had at first identified seven victims, but additional investigation turned up others. But after using forensic software to scan Bell’s personal electronic devices for evidence, detectives were able to identify additional victims.The police probe is ongoing.

The FBI is assisting in the case and has set up a hotline for parents whose children may have had contact with Bell. The number is 800-CALL-FBI.

Correction: A previous version of this story incorrectly reported that Carlos Deangelo Bell has been charged with child rape and infecting people with HIV. Bell actually faces various counts of child sex abuse and attempted HIV transmission to a minor. This version has been updated.