The fifth case showed images of a two-story home. Then Morrow’s monitor showed a bedroom with a naked woman on a blood-soaked bed, her limbs tied to each corner. On October 22, 2016, a neighbor discovered the body of Jasmine Maria Santos, age thirty-one, in her Indianapolis home. Santos was a bank teller and the divorced mother of a son, seven, and daughter, five. She had been bound in the same manner, sexually assaulted and stabbed more than three dozen times with a serrated knife, according to the autopsy report. Her phone and driver’s license were missing.

Morrow clenched her eyes for a moment to process the horror of what she was reading before moving on.

The next case changed everything.

In the early hours of April 8, 2017, Rhondell Felicia Hinson, age thirty, was alone and asleep in her town house in Louisville, Kentucky, when she was attacked by a man with a knife and wearing dark clothing. Hinson, a security officer who’d served with the Army National Guard, fought for her life, struggling with the intruder. She clawed at his masked face, neck and hands, tearing one of his latex gloves, then smashing a lamp against his head before jumping from her window. She fled to a neighbor’s house and suffered only lacerations to her arm and a sprained ankle.

But evidence recovered from the scene aided the investigation. It included a partial print. Investigators also recovered a section of cord, identical to the type used in previous attacks, and a partial shoe impression that, while a different shoe, was the same size as the impression recovered in earlier cases.

The quality of the partial fingerprint proved challenging for examiners. To date they had not succeeded in finding anything similar on record.

But interviews with Rhondell Felicia Hinson, the only known survivor, advanced the investigation, confirming a key fact common to all the cases. Prior to the attack, Hinson, a single woman, had frequented online-dating sites. When she’d arranged to meet a man, Ritchie Lee Bellanerd, at a restaurant, he failed to show up, leading Hinson and investigators to later suspect the attacker had targeted and stalked her.

Online-dating-site use was also a factor in three of the earlier homicides. And in the two other murders, the women who were living alone had conversed online about moving into a new residence. Again, this led investigators to suspect the killer hunted for victims online.

The FBI obtained court orders to examine all records of the dating sites and social-media sites used by the victims and visited by the suspect. The investigation yielded no concrete results. In the Hinson case, Ritchie Ray Bellanerd didn’t exist. In the other cases, investigators suspected the killer had used stolen or fictitious IDs and burner phones to communicate with, stalk and attack the women.