A 43-year-old Loudoun County man has been charged with using a computer to solicit a child under age 15, authorities said Wednesday.

Robert B. Rennie Jr. of Aldie was charged Oct. 24 after Loudoun County sheriff’s office investigators determined that he had used a Facebook account to contact and solicit young girls, according to the sheriff’s office.

Robert B. Rennie Jr., 43, of Aldie. (Loudoun sheriff's office)

The student had accepted a Facebook “friend request” from someone she believed was a fellow student at the middle school, who represented himself as “Kyle Kirts.” During conversation with the girl, Kyle Kirts solicited sexual activity from the child, authorities said.

The girl’s parents alerted school staff, who in turn alerted the sheriff’s office.

The subsequent investigation determined that Rennie was the creator and sole user of the account, according to the sheriff’s office.

Authorities also determined that Rennie portrayed himself as a student at Lunsford Middle School and had primarily young girls on his “friend” list. During chats with the young girls, the user known as Kyle Kirts would ask females to interact via a Skype account for sexual reasons, authorities said.

During the course of the investigation, several other victims were identified, sheriff’s office officials said.

The suspect made contact with children primarily from Lunsford Middle School and Mercer Middle School. The investigation is ongoing, and additional charges are possible, according to authorities.

Anyone with knowledge of a child who has had contact with the Facebook user Kyle Kirts or Rennie is asked to contact Detective P. Beaver of the Loudoun sheriff’s office Criminal Investigations Division at 703-777-0475.

Rennie is being held at the Loudoun County Adult Detention Center without bond, authorities said.

Update, 4:05 p.m.: Loudoun County authorities confirmed Wednesday that Rennie is a former employee of the Department of Homeland Security.

Through a fraudulent Facebook account, Rennie posed as both a middle school student at Mercer Middle School and as a 20-year-old college student at George Mason University, according to Loudoun sheriff’s office spokesperson Liz Mills.

Investigators think there could be upwards of 70 victims, Mills said.

“Most are in the Chantilly and Aldie area,” she said. “But it’s still early, and we are looking at the possibility of victims at high schools in other parts of the county as well.”

This post has been updated since it was first published.