His bond was set at $150,000.
Wilson told authorities that he will hire his own attorney, but he remained in jail Sunday afternoon and it was unclear if he had retained a lawyer, the Harris County Sheriff's Department said.
Wilson allegedly met the girl at a coffee shop on August 15, brought her to a hotel and paid her $500 for sex, Austin police Cmdr.
Wilson, 30, was arrested on Friday night at a hotel in Taipei, Taiwan, authorities said.More news: PNC Financial now part of Ripple money transfer network
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Mr Wilson runs Defense Distributed, a company that offers blueprints for creating 3D printed guns. "But we do know before he left, he was informed by a friend of the victim that she had spoken to police and police were investigating him for having sex with a minor", said Commander Troy Officer. The girl said she'd met the man on a so-called arrangement dating website and that he'd used the screen name "Sanjuro", according to police.
Nineteen states and the District of Columbia had sued the Trump administration to dissolve a settlement it reached with the company over allowing it to disseminate its designs for making a 3D-printable gun. He had missed another scheduled return flight to the USA, according to Commander Troy Officer with the Austin Police Department's Organized Crime Division.
The files could previously be downloaded for free but a federal judge issued a nationwide injunction last month that blocked the posting of the blueprints online. He began selling them for any amount of money to U.S. customers through his website.
Authorities worry the firearms are easy to hide and untraceable as there's no requirement for them to have serial numbers, which are a crucial part of any investigation of a crime in which shots are fired. Gun industry experts have said the printed guns are a modern method of legally assembling a firearm at home without serial numbers.
Wilson, a self-described "crypto-anarchist", has said "governments should live in fear of their citizenry".