A former California resident arrested in Indiana amid a federal sex crimes investigation agreed to a plea deal.

Matthew Christian Locher, 31, faced a nine-count indictment alleging sexual exploitation of multiple underage girls.

He pleaded guilty this week to one count of sexual exploitation of a child for the purpose of producing a sexually explicit visual depiction, according to the Department of Justice. He faces a minimum mandatory sentence of 15 years and a maximum of 30 years in federal prison.

Locher, whose various aliases included “The Hat,” “Matt the Hat,” “Hey There” and “Shark,” moved to Indianapolis in summer 2021 and was arrested January 2022. He’d relocated after federal authorities executed a search warrant at his home in California. He was taken back to California after his arrest and remained in federal custody.

Federal prosecutors said Locher targeted girls suffering from mental illness, inducing them to send him explicit photos and videos. The victims lived in various states, including Tennessee, California and Ohio.

He encouraged them to harm themselves, instructing one victim who struggled with an eating disorder to starve herself. When she disobeyed, he told her to record herself cutting her body.

Locher convinced at least two victims to send him videos and images showing them cutting themselves with razor blades.

In one case, Locher encouraged a 12-year-old Ohio girl to run away from home and come to California to engage in sex acts with him. Federal prosecutors said he encouraged the girl to kill her parents so he could take her to California and make her his “pet” or “slave.”

He told her he’d pick her up from her home if she “sent him photographs of her dead parents as proof,” according to court documents. The girl set fire to her parents’ home in an unsuccessful attempt to kill them.

Sentencing is scheduled for Jan. 23, 2023.

The investigation involved FBI, Homeland Security Investigations, the Los Angeles Police Department, the Springfield (Ohio) Police Department, the Shelby County (Tennessee) Sheriff’s Office and the New York City Police Department.