Cody Wilson, the US businessman whose company supplies 3D printed guns, has been charged with allegedly sexually assaulting a 16-year-old girl.
Wilson, who created blueprints for untraceable 3D-printed guns and posted them online, appeared in court in Houston after being deported from Taiwan, where he had fled after being told police were investigating allegations he had sex with the minor.
He was arrested by US marshals when he landed at the city's airport on Saturday and held in custody on a $150,000 (£114,740) bond.
Police accuse Wilson, who they say met the girl on SugarDaddyMeet.com, of meeting her in the car park of a coffee shop in Austin, before buying her coffee.
Investigators say he then took her to a hotel in the north of the city, where he allegedly assaulted her before paying her $500 (£383) in cash.
The age of consent in Texas is 17.
The girl told investigators that after having sex, he dropped her off at a Whataburger restaurant.
Wilson, a self-styled "crypto-anarchist", was arrested on Friday at a hotel in Taiwan by local police.
He covered his face with a scarf, hoodie and sunglasses as he left Taiwan, but was wearing none of those as he was led away by US marshals in Houston following his arrest.
Last month a federal court banned Wilson from posting the designs for the 3D printed weapons online free of charge.
More from United States
He has since been selling them for whatever his customers are prepared to pay, via his website.
Authorities worry the firearms are easy to conceal 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.