More 'savage and grisly' details emerge in Chicago deadly stabbing Men allegedly hatched crime as part of a fantasy built online, prosecutor says.

 -- A Northwestern University professor, as he allegedly stabbed his boyfriend whom prosecutors say he couldn't subdue, yelled for a second man to help him, according to a court document detailing the alleged murder.

Wyndham Lathem, a faculty member at Northwestern until he was fired this month after the alleged crime, and the second suspect, Andrew Warren, spent more than a week on the run together after, police say, they killed Lathem's boyfriend, Trenton Cornell-Duranleau.

Cornell-Duranleau, 26, was found stabbed to death at Lathem's Chicago apartment July 27. Both suspects were taken into custody in California Aug. 4 after a nationwide manhunt.

The suspects have not been arraigned to face a formal charge but the court document cites first-degree murder. Their attorneys say they are innocent.

Police Sunday described the crime scene as "savage and grisly."

Here are some of the details of the crime, according to the court document from the Cook County State's Attorney's Office:

Lathem, who lived in Chicago, and Warren, who lived in England, had allegedly communicated in an internet chatroom "about carrying out their sexual fantasies of killing others and then themselves."

Lathem allegedly paid for Warren to come to the United States for them to kill someone and then each other, and a few days before July 27, Lathem met Warren at Chicago's O'Hare airport. Lathem allegedly rented a room for Warren near his apartment.

On July 26, Lathem allegedly lured the victim to his apartment while texting Warren that they would kill him that night.

After Cornell-Duranleau went to sleep, Lathem texted Warren and told him to come over, and Lathem allegedly gave Warren a cellphone and told him to record the killing.

After Lathem allegedly stabbed his boyfriend repeatedly in the neck and chest, the victim woke up and began to scream and fight back.

Lathem allegedly couldn't control the victim and yelled to Warren to help him.

"Warren walked into the bedroom and placed his hands over the victim’s mouth to stop him from screaming. The victim bit defendant Warren’s hand and flailed his arms in the struggle," the court document said. "To silence the victim and stop him from moving, defendant Warren struck the victim in the head with a heavy metal lamp."

Both suspects stabbed the victim, the document said, alleging that "Warren used so much force on the victim that he broke the blade of one of the knives he used."

The court document said the victim’s last words to Lathem were, "Wyndham, what are you doing?"

While the victim bled to death in the bedroom, the suspects showered and tried to clean up the scene, the document said.

The document said a car was rented in Lathem’s name and that he left an anonymous cash donation of $5,610 at the Howard Brown Health Center in the victim's name.

The court document said after the suspects fled Chicago, Lathem "called the front desk of his apartment building and told front desk security that apartment 1004 should be checked, there had been a crime committed in that room."

Responding authorities found that the victim had been stabbed 70 times and his head was nearly decapitated, the court document said.

While the suspects were on the run, Lathem sent a video message to his parents and to friends, admitting "that he killed the victim and that the murder was not an accident," but saying, "he is not the person people thought he was," according to the court document.

"He admitted that the victim trusted him completely and felt safe with him but that he betrayed that trust," the document said.

The defendants at one point fled to Lake Geneva, Wisconsin, where Lathem went to the Lake Geneva public library and made a $1,000 cash donation to the library in the victim's name, the document said.

Lathem's attorney, Barry Sheppard, told ABC News today, "We are representing a brilliant scientist who at this point we believe is innocent."

Sheppard said Lathem has not yet entered a plea but plans to plead not guilty.

Sheppard said "we don't accept the facts" presented in the court document, adding, "we are conducting our own independent investigation that will differ substantially from the [court document]."

Sheppard said no arraignment date has been set.

Once in custody, Warren allegedly admitted to helping Lathem in the killing, and when asked whether there were any other potential victims, Warren allegedly said there were but said he did not know if that person showed up at Lathem's apartment the next morning after they fled the crime scene.

Warren allegedly demonstrated for officers how he and Lathem stabbed the victim and Warren said he did not record the killing on the cellphone, the court document said.

Kulmeet Galhotra of the Cook County Public Defender's office, which is representing Warren, told ABC News today that Warren is "presumed innocent. And we have just been appointed, so we're going to begin our investigation of the case."

"I anticipate that in a few weeks there will be an arraignment at which he will be entering a plea of not guilty," he said.

ABC News' Dom Proto contributed to this report.