Two teenagers in Frederick, Maryland, were charged and a third remains at large for allegedly kidnapping and raping a classmate, according to court documents filed last week.

The arrested were identified as 19-year-old Victor Antonio Gonzalez-Guttierres and 17-year-old Edgar Natanal Chicas-Hernandez.

The investigation into the case began Sept. 5, when Detective Anthony McPeak and Officer 1st Class Marlon Alvarez went to interview a high-school-age girl about an assault that she said took place on Sept. 1, the Frederick News-Post reported.

The girl narrated the series of events to the police, saying the three boys grabbed her by the hair as she was walking home on the day of the incident. She recognized two of them as her classmates, while the third had his face covered. She said that they first slapped her, and then one took out a knife and harmed her physically, the court documents stated.

The boys took away her cellphone and dragged her to a nearby vehicle. The girl told the police that they also told her that they were carrying out the orders of a younger female acquaintance of the victim.

This younger female acquaintance was identified in charging documents as the suspected mastermind of the crime.

The girl's mouth was shut by forcing a rag into it and she was taken to a separate location. According to the charging documents, here Chicas-Hernandez and Gonzalez-Guttierres raped her.

Gonzalez-Guttierres is from El Salvador, ABC News reported citing the U.S. Immigration and Customs Enforcement.

The agency said in a statement that it has lodged an immigration detainer for him.

Court documents also state that the third person involved in the crime used a cellphone to record the crime. 

“The third, unidentified man mentioned in the charging documents has not been charged. ... As the investigation continues, however, we do anticipate there being additional charges in this case,” said Lt. Clark Pennington, commander of the police department’s Criminal Investigations Division, according to the Frederick News-Post

However, what has baffled the investigators in the whole incident was that the girl was first kidnapped, driven to another location and then raped. 

“This is very, very rare in my experience,” said Detective Joe Palkovic, an assistant supervisor in the Frederick Police Department’s Criminal Investigations Division. “The violence of it and the nature of the crime, the fact that this involves someone laying in wait, kidnapping the victim and then taking her to a separate location to rape her, is very rare.”

The motive of the act is yet to be figured out.

“We’ve recovered messages on a social media site where there is conversation between the suspects and this other juvenile — communication before and after the assault. We do believe there is some level of conspiracy between these individuals,” Lt. Clark Pennington, commander of the Frederick Police Department’s criminal investigations division, said, a report said.