KANSAS CITY, Mo. - In the end, it wasn't a fingerprint or a blood spatter that led authorities to the woman suspected of strangling a mother-to-be and cutting the baby from her womb.
It was an 11-digit computer code.
Police zeroed in on Lisa Montgomery by trolling computer records, examining online message boards and - most important - tracing an IP address, 18.104.22.168, to a computer at her Melvern, Kan., home.
"That in and of itself led us to the home," FBI spokesman Jeff Lanza said of the IP, or Internet protocol, address, the unique number given to every Internet-connected computer.
Investigators say that, just before the slaying, Montgomery corresponded over the Internet with the victim, Bobbie Jo Stinnett, about buying a dog from Stinnett. The same technology that makes instantaneous communication possible enabled authorities to crack the case in a matter of hours and rescue the premature baby.
Montgomery, 36, made her first appearance Monday before a packed courtroom in Kansas City, Kan., where her attorney refused to waive her right to preliminary and identity hearings. Both hearings have been scheduled for Thursday morning.
Montgomery is charged with kidnapping resulting in death.
Her attorney and Assistant U.S. Attorney Terra Morehead declined to comment. Authorities have said Montgomery confessed to the crime. The 4-day-old girl was released from a hospital in Topeka, Kan., Monday.
The suspect's husband, Kevin Montgomery, told reporters outside the courthouse he knew nothing about his wife's alleged actions. He has not been charged with any wrongdoing.
"My family has suffered a tragedy, but I am not the only family," he said. "This has to be as hard or harder on them as it is on me. I sure hope they get as much support from their church and community as I have, because we are all going to need it."
Within hours of Stinnett's killing Thursday at her home in Skidmore, Mo., investigators realized that information on her computer might help find the killer.
Stinnett, 23, raised rat terrier dogs at home and had been expecting a potential customer the afternoon she was killed.
When Stinnett's body was discovered, detectives took her computer.
At the lab, clues seemed to pour out of the computer within minutes - who Stinnett had been e-mailing, what sites she had been visiting. Important tips from the public came in, too. Among them: A North Carolina dog breeder pointed to communications on a rat terrier message board.
"My adrenaline just started rushing," said the breeder, Dyanne Siktar. "I knew they could track the IP."
Investigators traced an IP address to a dial-up connection from Montgomery's home in Melvern, about 120 miles southwest of Skidmore. On Friday, less than 24 hours after the slaying, investigators found the baby at the home and arrested Montgomery.