CHICAGO (CBS) — Andrew Warren, 56, and Wyndham Lathem, 43, were held without bond Sunday after prosecutors laid out details of a bizarre and twisted murder of Lathem’s boyfriend during the suspects’ first Cook County court appearance.

CBS 2’s Sandra Torres reports that we now know that Warren, a British nationalist and former University of Oxford employee, confessed to police. This is how prosecutors learned what motivated the crime that allegedly was part of a sexual fantasy.

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“Defendant Warren told the police that the victim had no idea what was coming,” said Natosha Toller, the Assistant State’s Attorney.

As prosecutors laid out the case against Warren and Lathem, a former Northwestern University professor, they said it was premeditated murder that was supposed to be videotaped.

“For several months, communicated through an Internet chat room about carrying out their sexual fantasies of killing others and then themselves,” Toller said.

Both Warren and Wyndham were quiet in court, as prosecutors went through the timing of events, saying Lathem paid for Warren’s ticket to travel from England to the U.S. to fulfill their fantasy.

“After the victim went to sleep in defendant Lathem’s apartment, Lathem text defendant Warren that it was time to kill Trenton [Cornell-Duranleau].”

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Once in the apartment, prosecutors say Warren used a drywall knife with a six-inch blade to carry out the attack on July 27, which resulted in the killing of Lathem’s boyfriend, 26-year-old Trenton Cornell-Duranleau.

“Defendant Lathem then stabbed the victim over and over in the next and chest area,” Toller said.

Warren was supposed to videotape Lathem stabbing Cornell-Duranleau — Lathem’s boyfreind — as he slept, but the victim woke up and began to fight back, prompting Lathem to call out to Warren for help, prosecutors said.

The medical examiner reported that Cornell-Duranleau had a total of 70 stab wounds and that his head was nearly decapitated.

“Our client, Dr. Wyndham Lathem, is a distinguished microbiologist as an associate professor at Northwestern,” said attorney Barry Sheppard.

And while defense attorneys presented that information in court, the judge denied bail for both men saying, “the heinous facts speak for themselves.”

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Lathem did not make statements to police, but prosecutors say while on the run, he sent a video to family and friends saying the murder was not an accident and that he is not the person people thought he was.