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.