EASTON, Pa. – Even in prison, a convicted sex trafficker continued to orchestrate his trade, Northampton County authorities say.

Already facing a potential life sentence for preying upon women, Seth R. Mull, 31, was charged Friday with promoting prostitution from inside Northampton County Jail. He is accused of using a prison-issued computer tablet to groom a woman to sell herself for him, reported The Morning Call.

Mull’s communications with the woman, who is not in prison, included demands that she “embrace group sex,” go to “sex parties and orgies” and market herself sexually online, according to court records.

The accusations featured similar gaudy details that came out during Mull’s trial in December, including a “sex slave contract” that he reportedly asked the woman to sign and send to him.

“I want control of all of you but it starts before we ever touch one another,” Mull is accused of writing. “You need to give up control to me.”

Authorities call Mull, of Lower Saucon Township, a serial predator who created victims starting when he was 13 years old. On Dec. 7, he was convicted of rape, kidnapping and human trafficking charges after a trial in which four women testified he viciously assaulted them at hotels in the Lehigh Valley and Philadelphia.

Then came incarceration and his creative designs at continuing crime. Authorities said Mull’s prison communications were done over an electronic tablet that the jail began making available to inmates in November. The privileges can facilitate illegal activity. As a growing technology in prisons, it allows inmates to text, phone, and in some cases video chat with friends and family for a fee.

“The victim stated that when she started talking with inmate Mull, he appeared to care about her,” a county detective wrote in the arrest affidavit. “She said it then became all about sex and having sex for money. She said that there was a constant pressure from him to ‘get things going,’ to start the sex webcams for money.”

Northampton County Jail has about 100 tablets, with which prisoners can file grievances and access legal research and the prison’s manual, said Kenneth Kraft, the jail’s public safety administrator. Phone calls and text messages are monitored, just like the prison’s traditional phones, Kraft said. Furthermore, for a fee, inmates can purchase sanitized movies, similar to those offered on an airplane, he said.

“It’s a way to keep people occupied and it is also good as a deterrent, because if you lose the tablet, you have nothing to do, and it’s boring here,” Kraft said.

According to authorities, Mull came under investigation in January, after Kraft discovered the ongoing communications between Mull and the woman.

Specifically, the affidavit quotes from those messages beginning on Dec. 15 — eight days after Mull’s conviction — and ending Jan. 3, the day after Kraft met with a county detective.

How the woman and Mull came to correspond was not specified by authorities. They began communicating in August through letters and phone calls, according to the affidavit, with the woman telling investigators she was having trouble with her marriage at the time and found Mull “friendly and supportive.”

Sentencing in Mull’s human trafficking case is scheduled March 15 before Judge Stephen Baratta, according to The Morning Call.

Mull has been jailed since his arrest in October 2017, when police in Bethlehem responded to a Holiday Inn Express. It was there a 25-year-old woman reported that he raped her, strangled her, burned her with a torch lighter and threatened to kill her.

That woman was just one of four who took the witness stand against Mull at his trial. The victims provided details of assaults that occurred over an eight-week span. The women testified that Mull kept them in terror, beating them, strangling them and, in some cases, selling them to other men.

A fifth woman was also permitted to testify. As a result, she said Mull raped her in 2014 while they both lived in Pittsburgh.

Mull’s public defender, Matthew Potts, did not return a phone call seeking comment Friday. He argued at trial that the sexual encounters were consensual.

Consequently, Kraft said Mull is no longer permitted a tablet.