Serial killers' messages — whether they've been scrawled in lipstick or posed in cryptic symbols — have often inspired responses from police via the media. Some communications experts call the exchange a public "cat-and-mouse game;" others say it's a savvy way to keep clues coming.
After three weeks of Washington, D.C.-area sniper shootings, 10 of them fatal, Montgomery County Police Chief Charles Moose turned to the cameras Monday to discuss a message left for police — a message now believed to be the work of the sniper.
The lead investigator said: "The person you called could not hear everything you said. The audio was unclear and we want to get it right. Call us back so that we can clearly understand," said Moose, who has been leading the hunt.
On Tuesday afternoon, Moose said police had received another message and disclosed details from an earlier communication.
Later Tuesday night, Moose responded to several reports about the contents of a note left near the scene of a shooting Saturday in Ashland, Va.
The note, which investigators believe was from the sniper, said that he had made at least five calls to police that had been "ignored" by operators answering the phones, ABCNEWS has learned.
Chief Gil Kerlikowske of the Seattle police department says it's no surprise that investigators in this case are willing to communicate through the media.
"Given the length of time this case has gone on, and the impact it has had, I would be using every technique possible, just as they are," Kerlikowske said.
Working to Build a Profile
When investigators use the media to communicate with a suspect, it can result in a continuing dialogue and possibly additional clues, said Joan A. Deppa, an associate professor at the S.I. Newhouse School of Public Communications at Syracuse University.
"I think it's a wise thing to do," Deppa said. "One of the things about communicating is that people will always manage to tell something about themselves, even when they don't mean to. It's the devil we don't know that's making our lives miserable," she said.
Tomas Guillen, a professor at Seattle University who specializes in communication between serial killers and police, says messages from the killer can help police learn something about their identity, but it rarely leads to a direct identification of the killer.
"I think it's possible, but it's been very rare, Guillen said on ABCNEWS' Good Morning America Tuesday. "He's playing a cat-and-mouse game."
Historically, few serial killers have been nabbed through communications alone. "Son of Sam" David Berkowitz, the serial killer who killed six people and wounded seven in New York City, had a dialogue with police through many letters, but was caught only after he received a parking ticket near the location of one of his murders.
San Francisco's "Zodiac Killer" has never been found, despite the 21 letters the killer sent to a local paper.
The "Unabomber," Ted Kaczynski, was caught after he used the media to communicate with the world. His brother recognized Kaczynski's writing style and turned him in after reading the bomber's 35,000-word "manifesto," which he demanded newspapers print.
Messages and Notes Offer Details
In a paper published in the Journal of Criminal Justice titled "Serial Killer Communiques: Helpful or Hurtful," Guillen reviews cases in which serial killers communicated with investigators and/or the media.
In most of the cases, he comes to the conclusion that the discourse did not lead directly to an arrest, but it often, as in the case of the "BTK" serial killer of Wichita, Kan., offered details about whether or not the killer planned to strike again.
The communication offered by the D.C.-area sniper, in the form of a letter that reads "your children are not safe anywhere at any time" offers the same insight as that of the "BTK" killer.
The BTK killer (short for bind them, torture them, kill them) killed at least six people in the 1970s and was never caught. He sent letters and poems to the local newspaper and television station.
Guillen admits that investigators in the D.C.-area sniper case must respond to the shooter's messages.
"That's the only way he [Moose] can directly try to appeal to this killer," Guillen said. "I commend police for trying to do that, because they have to communicate with him, but it's very difficult, because it's going through the media."
James Edward Starrs, a professor of Law and Forensic Sciences at George Washington University, worries that the public dialogue might backfire in some cases.
"The downside is that it may have an encouraging effect to have them continue," Starrs said. "That you have elevated him and put him on a platform and that public platform spurs them to further killings."
Deppa says it's important for police to be extremely careful about what they decide to tell reporters in this case. "We can't report what we haven't been told," Deppa said.
"The information must be judged by law enforcement on a case-by-case basis. There is, of course, some information that the public really needs to know … information that would influence people to act differently in order to protect their children," she said.
ABCNEWS.com's Maryann Bennett and ABCNEWS' Bob Woodruff in Ashland, Va., contributed to this report.