As a married father of two, Cub Scout leader and church president, 59-year-old Dennis Rader -- the suspected BTK serial killer -- does not fit the stereotypical profile of the seedy-looking, antisocial serial killer.
FBI and police working on unsolved serial cases around the country now plan to closely study this unusual suspect.
"One of the things I think we need to do now is learn from him," said former Wichita, Kan., police chief Richard Lamunyon. "We need to know why he did it, how did he pick his victims, what drove him."
The details Rader offers may help police struggling with similar open cases better understand how serial offenders think.
According to criminologists, at any given time there are at least 25 to 100 active serial killers in the United States. The FBI is currently assisting in 16 such cases.
But while there are similarities in the way serial killers operate, police say Rader's arrest is a startling reminder that investigators need to follow the evidence and rely less on profiles, which can sometimes be misleading.
"In reality, most serial killers look like the man next door," said former FBI behavioral scientist Peter Smerick. "They do not look like Charles Manson."
For example, not all serial killers are antisocial.
John Wayne Gacy was convicted of killing 33 young men and boys in the Midwest in 1980. Gacy, however, was chaplain of a local junior chamber of commerce chapter and liked to pose as a clown for sick children in hospitals.
Likewise, Ted Bundy -- who confessed to 31 murders in the 1970s -- was a polished law student who often socialized with police.
What makes serial killers so difficult to catch, say police, is that they are smart and flexible.
ABC News' Pierre Thomas filed this report for "World News Tonight."