TULSA, Okla. (KFOR) – Officials say a school security guard has been taken into custody following allegations of inappropriate behavior.

Officials with the Tulsa Police Department say they began investigating following a tip to Union Public Schools Freshman Academy.

School officials say they received information that a security guard employed with the school system was having inappropriate contact with several teenage students.

Detectives say several students claimed that Carlos Hopkins messaged them on Snapchat and Instagram. They say the messages started out with casual conversations and then turned sexual with Hopkins allegedly asking questions about their genitalia.

Police allege that Hopkins offered money to the students in exchange for nude photographs.

On Thursday, Hopkins was charged with seven counts of using technology to engage in sexual communication with a minor.

Officials say several other students came forward after the initial investigation, so they say additional charges may be added.