Veteran FBI agents experienced in tracking killers believe authorities may have achieved a breakthrough in the massive manhunt for the elusive serial sniper who has been striking seemingly at random across the Washington DC area. The cryptic messages that have been exchanged between police and someone who they believe may be the sniper could yield important clues that lead to the killer's arrest.

Unlike most crimes, veteran FBI agents say the most difficult part of tracking this killer is the fact that the sniper leaves little evidence, may have no criminal record and appears very skilled at shooting and quickly getting away without detection.

William Sessions spent six years as director of the FBI. "This is a very careful person with very astute planning and he has all the advantage of knowing what he's going to do and nobody knows where he is going to be or strike," said William Sessions. "He obviously has tremendous training and instincts."

But after three weeks of seemingly random killings, the elusive sniper now appears to be trying to communicate through cryptic messages for the police in what could be the biggest break in a case that has left investigators with too few facts to even release a description of the killer. "This is undoubtedly the most promising lead," said Rick Hahn.

Rick Hahn spent 30 years as an FBI agent, investigating terrorism and such high profile cases as the Oklahoma City bombing and the first attack on the World Trade Center in 1993. "Very much the whole act is laid out to draw attention to himself, to draw some sort of point that he wants to make out into the public eye," he said. "And in order to do that and get the recognition that he wants deep down inside, eventually he will reveal himself. Hopefully, he will either surrender himself or he will communicate long enough and well enough so that the law enforcement agencies will have a chance to apprehend him."

Leading the sniper investigation is Maryland's Montgomery County Police chief Charles Moose who has begun using the media to send messages back to the killer, in words only the sniper apparently understands. This, after the killer left a message for the police at the scene of a shooting in Virginia Saturday night. "To the person who left us a message at the Ponderosa [restaurant] last night, you gave us a telephone number," he said. "We do want to talk to you. Call us at the number you provided. "

"I think he's taunting the police," said Candice Delong.

Candice Delong spent 20 years as an FBI agent focusing on counter-terrorism, including helping catch the serial package bomber Ted Kaczynski better known as the Unabomber, in 1996. "He may very well be someone who applied to a police department and got turned down, she said. "Where do you see snipers in our culture? Police departments, and the military and probably the CIA and Secret Service. He very well may have applied to one of those and was turned down and now he's going 'Oh yeah? Watch this.' "

Despite daily news conferences, police are revealing very little about the investigation, only that they are confident that one of the most intensive manhunts in the Washington region ever is making progress. But with no arrests and little to reassure the public, this unusual attempt to lure the sniper into a dialogue, at times through the media could be their best chance yet toward catching the killer.