Cody Wilson, the self-described crypto-anarchist at the center of the 3D printed gun debate, decided to fly to Taiwan — right after he learned that Austin police were investigating him for allegedly paying a 16-year-old girl for sex.

“Today Mr. Wilson is not in custody, and his last known location was Taipei, Taiwan,” Troy Officer, commander of Austin’s organized crime division, said in a press conference on Wednesday. “We also know that Mr. Wilson missed a scheduled flight back to the United States.”

Wilson did not respond to VICE News’ request for comment.

Wilson, 30, is best-known for his legal battles with the government over his decision to publish blueprints for 3D-printed guns online. Now, he’s now been charged with a second-degree felony for sexual assault of a minor and, if convicted, could spend up to 20 years in prison.

Officer said that it wasn’t clear why Wilson went to Taiwan, but suggested that the timing of his departure was suspicious. “We know that Mr. Wilson frequently travels for business,” Officer said. “We don’t know why he went to Taiwan, but we do know that before he left he was informed by a friend of the victim that she had spoken to the police and they were investigating him for sex with a minor.”

A warrant has been issued for Wilson’s arrest, and his name has been entered into the national law enforcement computer, Officer said. “We’re also working with national and international law enforcement partners to locate him and bring him to justice.”

According to charging documents, Wilson used the website SugarDaddyMeet, which connects older men with younger women. Users have to be at least 18-years-old; After having sex in a hotel, however, Wilson paid a girl, who was only 16-year-old, $500 in $100 bills.

Officer said that investigators interviewed the victim, and said that, if anything, she looked younger, not older, than 16. He also explained that the organized crime division was handling this case in the event that there was a child sex trafficking element linked to the case.

Wilson sued the State Department in 2016 year on First Amendment grounds when officials asked him to remove YouTube videos explaining how to make his so-called “liberator,” a 3D-printed gun. But the Trump administration abruptly settled his case a few months ago, which cleared the way for him to resume uploading blueprints, prompting an onslaught of political and legal backlash.

Wilson is also known for founding Hatreon, a crowdfunding platform popular among white nationalists and neo-Nazis who were shut out of mainstream platforms after the violent rally in Charlottesville.

He and an associate were originally scheduled to speak at a pro-gun conference in Chicago this weekend organized by Second Amendment Foundation. They are no longer listed as speakers.