WASHINGTON (DC) — District of Columbia Police Chief Charles Ramsey said Sunday that surveillance video from the apartment building where a Washington intern lived was useless by the time police began investigating her disappearance.

"There is a video system there," Ramsey said on ABC's "This Week." However, he said, "The tape quality is very, very poor. They do tape over the different tapes during the day.

"It was a week before we even knew about the missing person, so unfortunately some of the evidence that we would have had, had we known sooner, we won't have available to us."

Chandra Levy, 24, of Modesto, Calif., was last seen April 30, a few days after she finished an internship with the federal Bureau of Prisons.

Saturday, police interviewed Rep. Gary Condit, D-Calif., a second time. Condit has described Levy as a "good friend." Police say he is not a suspect in the case.

Terrance W. Gainer, Washington's executive assistant chief of police, said on CNN's "Late Edition" that the purpose of the interview was to "get some clarity, when he may have last saw her, spoke to her, what he knows about her."

Asked if the interview with Condit was useful, Gainer said, "I think all the information we gather is helpful." He declined to reveal details.

"I think what we need to convey to anybody who wants to give us information is we're going to keep that close to the chest," Gainer said.