Updated at 5:30 p.m. Sept. 23: Revised to include that Cody Wilson has been brought back to the U.S.

The man at the center of the debate over 3-D printed guns is accused of paying an underage girl to have sex with him last month at an Austin hotel.

Cody Wilson, 30, faces a charge of sexual assault, according to an arrest warrant affidavit filed Wednesday. U.S. marshals said Friday that Wilson had been arrested in Taipei, Taiwan.

He was brought back to the U.S. and jailed Sunday in Harris County, the Associated Press reported.

Cody Wilson (U.S. Marshals Service)

Wilson had missed a scheduled flight back to the U.S., Austin police Commander Troy Officer said at a news conference Wednesday.

"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," Officer said.

The girl, who is 16, told police she began communicating with a man who used the screen name "Sanjuro" on a site called SugarDaddyMeet.com, the affidavit stated.

The man identified himself as Cody Wilson and described himself as a "big deal." They exchanged nude photos and text messages and agreed to meet Aug. 15, the affidavit stated.

Wilson reportedly picked the girl up in the parking lot of Bennu Coffee in the 500 block of South Congress Avenue in Austin. They drove in a vehicle that matches the one registered to his business to the Archer Hotel near The Domain, and parked the SUV at valet, the affidavit stated.

They had sex and Wilson paid her $500, according to the affidavit. He dropped her off later that night at a Whataburger on West Slaughter Lane.

Surveillance footage captured the two at the coffee shop, hotel and Whataburger, according to police documents. Wilson's driver's license photo matched the image on the "Sanjuro" profile.

Wilson could not be reached for comment Wednesday.

Cody Wilson showed the first completely 3D-printed handgun, The Liberator, at his home in Austin. (File Photo / Austin American-Statesman)

Wilson designed and built a functioning 3-D printed gun in 2013 and posted the design files to the internet, where the public could use it. The government ordered him to take the files down, citing regulations for exporting firearms.

His company, Defense Distributed, partnered with the Second Amendment Foundation to sue the State Department in 2015. They settled earlier this summer after the State Department removed the 3-D gun-making plans from a list of weapons or technical data that are not allowed to be exported.

In July, a federal judge in Seattle issued a temporary restraining order barring him from posting the files online, but Wilson said in August that he was going to sell the blueprints on his website anyway.

Staff writer Dana Branham contributed to this report.