A former instructional assistant at a middle school in Maryland who told authorities he’s HIV positive has been arrested for allegedly sexually abusing several male students, authorities said.

Carlos Deangelo Bell, 30, was arrested Friday at his Waldorf home after being indicted by a grand jury in Charles County on charges of production of child pornography and three counts of second-degree assault, prosecutors announced Monday.

An investigation was launched in December after investigators got a tip about possible inappropriate behavior between Bell and a student while he was coaching track at La Plata High School. Bell, who also had worked as an instructional aide at Benjamin Stoddert Middle School, was immediately removed from the school and banned from continuing his coaching duties.

Detectives who searched Bell’s work computer at the time found nothing suspicious, but a subsequent search of his personal computer revealed data linking him to the production of child pornography. Investigators also determined that Bell sexually abused “several males” on school grounds, his home and potentially other locations as well.

Bell victimized at least seven children, NBC Washington reports. Charles County Sheriff Troy Berry told the station that authorities aren’t aware that any of the alleged victims have contracted HIV, but said additional testing will be conducted.

Bell was identified by authorities after a parent of one of his alleged victims found explicit text messages on the boy’s phone. Child pornography was also discovered on Bell’s personal electronic devices, Berry told the station.

Additional charges in the case are likely, including additional sex offenses and first-degree assault, Berry said, adding that there may be more victims as well.