Cody Wilson, the Austin, Texas, man who set off a national debate over plastic guns by posting plans online for making them with a 3D printer, has been charged with sexual assault, according to Austin police.

An arrest warrant issued Wednesday said a juvenile woman, under the age of 17, told investigators that a 30-year-old man paid her $500 to have sex with him in mid-August at an Austin hotel. She said she met the man online and exchanged text messages. In one of them, police say, he identified himself as Cody Wilson and said he was "a big deal." The two also exchanged explicit photos of each other, she told investigators.

But Wilson was not yet in custody and his last known location was in Taiwan, police said Wednesday afternoon at a news conference.

"Today, Mr. Wilson is not in custody and his last known location by the Austin Police Department was Taipei, Taiwan," said Commander Troy Officer, of the Austin Police Department's organized crime unit. "We also know that Mr. Wilson missed a scheduled flight back to the United States."

Wilson left to Taiwan after being told by a friend of the 16-year-old victim that she had gone to police and that he was being investigated for having sex with a minor, Officer said.

"Mr. Wilson left the country before we could seek an interview," he said.

Detectives say police matched information from Wilson's driver's license to data he posted at the website where he met the woman.

Surveillance video of a coffee shop where the two met showed the man arriving in a black SUV similar to a vehicle registered to Wilson, the police report said. Video from the hotel where the woman said they had sex showed Wilson getting out of the black SUV with her, the report said, and surveillance video from inside the hotel showed Wilson and the woman getting out of an elevator and walking to a guest room.

Wilson was charged with having sex with an underaged person, a second-degree felony in Texas, punishable by a sentence of up to 20 years in prison and a fine of up to $10,000.

Phone calls to Wilson on Wednesday were not returned, and no court records were available to show whether he had retained a lawyer.

Officer said that police were notified about the incident by a counselor, who, like school teachers and doctors, are required by law to notify police about sexual assault cases.

Police then spoke with the victim, who cooperated with the investigation.

Wilson began posting directions for making plastic guns in late July, after the Trump administration dropped its opposition and settled a lawsuit that had prevented him from making the files available for download. When fed to a 3D printer, the plans allow a user to make the parts necessary for assembling fully functioning handguns or rifles.

Lawsuits filed by several states resulted in court orders issued last month that blocked Wilson from keeping the plans online. In response, Wilson said he would send the plans by mail to those requesting them.