"It is difficult terrain to search," Ramsey said on Good Morning America. "It's an urban forest. The remains were found at the base of a cliff. It's difficult to even get to. We did the best we could to try to search 1,700 acres of parkland. If the body was there during the search, we would have missed it, but you could have stood next to it and not seen it.
"That is the presumption that the body was there at the time of the search and not dumped afterwards," he added.
Ramsey would not confirm or deny reports that the remains were found in a shallow grave, but said that they were "covered with a thick underbrush of about a foot thick."
Guandique may have caught investigators' attention not only because of the location where he committed his crimes, but because Levy was apparently jogging with a Walkman radio when she disappeared, like the man's two victims.
Those two women, who were attacked in mid-May and on July 1, 2001, were both jogging with Walkman-like devices. Both were grabbed from behind and threatened with a knife.
However, each of those women was taller than Levy and one was trained in self-defense, and both were able to get away, though he shoved one of his victims into a ravine just off the jogging trail before she was able to elude him.
The judge who sentenced Guandique rejected his defense that all he wanted to do was steal the women's personal radios, and said his behavior was "more predatory," according to Amy Keller, a senior staff writer for Roll Call, a newspaper that covers Congressional matters.
The victims described the attacks as vicious, Keller said on Good Morning America.
Searched Three Times
Still, police do not have much to work with. Law enforcement sources told ABCNEWS that Levy's remains are so decomposed they may never learn how she died.
The Levy case generated national headlines after reports surfaced that the young woman had been linked to Rep. Gary Condit, D-Calif. More than 200 members of the media arrived in Rock Creek Park within hours of the announcement that a body had been found there.
Levy's remains were found Wednesday morning by a man walking his dog, looking for turtles in the park.
Levy's apartment was near the park, which police searched three times last summer after analysis of her computer revealed she had done a search for directions to the Klingle Mansion, a historic home in Rock Creek Park, the day she disappeared.
The young woman's body had apparently been in the park for a long time, and the bones were not all in one location, Ramsey said on Wednesday. Investigators still did not know this morning whether the area where the remains were found was where Levy died, or whether the body had been moved.
Ramsey said Susan and Robert Levy, the young woman's parents, learned of the identification of the remains while watching the news, despite his efforts to make sure they were informed first.
Sources have said Rep. Condit, 54, admitted to police that he had an affair with the young woman — whose hometown, Modesto, is part of his district — right up until she disappeared.
Police have stressed Condit is not considered a suspect, but the scandal hurt the once-popular lawmaker's standing with his constituents. The six-term congressman, who is married, lost his reelection bid to a former aide in a Democratic primary in March.
A memorial service for Levy will be held Tuesday at Modesto's Community Center, a family spokeswoman said. ABCNEWS' Pierre Thomas contributed to this report.