Unlike most other alleged serial killers, a slip-up by Ridgway was not primarily what led to his arrest. He was not caught during an attempted carjacking like the Night Stalker, Richard Ramirez, who killed at least 16 people in Los Angeles in 1985 or arrested following a traffic stop like Bundy.
"Most profilers say serial killers don't learn from mistakes in their previous killings, but I believe they do," said Tod W. Burke, professor of criminology at Radford University and a former police officer. "They try to improve on their previous effort. You know how the more you do something, the better you get at it? Well, there comes a point where you peak and you can only go down. With serial killers, a greed factor will set in where they'll believe the more they kill and get away with it, the easier it will be. And that's when they get sloppy and get caught."
The Thrill of the Chase
Experts hesitate to generalize the characteristics of serial killers because there are several kinds of them driven by different sets of motives. Some are thrill-seekers, who see their killings and the police pursuit as a game. Experts say they love the attention of the media and the pursuit by police — and the fact that they are able to evade authorities.
"You're likely to see these kind of killers send a message with their killings," said Burke. "They tend to keep a record of their killings. It would not surprise me to see these guys keep [newspaper] clippings of their murders. They enjoy one-upmanship, get joy from foiling the efforts of the police."
Some serial killers are mission-oriented, believing that they are doing society a favor by getting rid of certain people, such as prostitutes, or by making a statement against particular trends, such as the growth of technology. Others are motivated by power and control — Experts say they tend to get more of a thrill out of seeing their victims cower and hearing them scream than from the kill itself.
Still, experts say the motives in serial killers are deeply personal, and they enjoy being elusive and the celebrity they gain. And they tend not to be apologetic.
"With all of them, their motives tend to be total, deep and personal," said Rustigan. "They feel no guilt, no remorse and have an attitude of total disdain towards their victims.… There's a self-importance that runs in all of them."
And that self-importance — or ego — has been some serial killers' downfall. When it appears that a string of multiple slayings may never be solved, experts say serial killers tend to let their egos get in the way, especially if they feel they are not being portrayed correctly in the media or they're feeling upstaged by other events.
"With the Unabomber, for example, he demanded that The Washington Post and The New York Times publish his manifesto," said Rustigan. "You get the feeling that if he had just laid low, he may have remained on the loose to this day. His own brother saw the manifesto in his home and he then contacted authorities. I feel he felt upstaged by the Oklahoma City bombing, which made everything he had done up to that point seem like nothing."
The Danger of Confessions
But that hasn't been the case with Ridgway. He appeared to lay low for years and was only formally arrested after advances in DNA technology gave investigators enough evidence to bring him into custody, and made prosecutors comfortable enough to bring murder charges.