A junior sailor was charged in Chicago this week after prosecutors said he convinced a 13-year-old girl to send him sexually explicit photos and videos of herself.

Fireman Apprentice Ethan Knez, 21, used a website and messaging app to begin communicating with the Michigan girl in February of 2018, according to a complaint filed Monday in U.S. District Court for the Northern District of Illinois.

Knez’s service record shows he was a student at Training Support Center Great Lakes, a service school north of Chicago, at the time.

His court-appointed defense attorney, Robert Seeder, did not return requests from Navy Times for comment.

Last March, the girl’s father alerted authorities that his daughter had sent and received pornographic images from adult men, according to the complaint.

The parents turned the girl’s phone over to authorities, who found a messaging app account with the screen name “madnezz19” that they later linked to Knez, court records allege.

While Knez allegedly sent the girl explicit images of himself and she did the same, the child “talked about issues with her parents, the desire to run away, and alluded to taking pills in a possible suicide attempt,” prosecutors wrote.

In one series of messages, the girl told Knez she had been sexually assaulted at school, the complaint states.

At one point, Knez sent the girl an intimate image of himself “while wearing a navy-color blue U.S. Navy shirt,” according to the complaint.

The Naval Criminal Investigative Service got involved when Knez was determined to be a military member, the complaint states, and he told authorities in January that “he also instructed approximately 15 other females under the age of 18 to produce similar sexually explicit images and videos and that they sent these images and videos to him at his request.”

“Knez said he believed the youngest victim was 15 or 16 years old,” a NCIS special agent wrote in the complaint. “When I confronted Knez with (the 13-year-old girl’s) age, Knez said, ‘if that’s what it says, then that’s what it is.’”

An Indiana native, Knez enlisted in the Navy on Nov. 28, 2017.

He remains in custody, according to Navy and federal court records.

The story was first reported by the Chicago Tribune.