Prosecutors announced Thursday that they will not retry a man convicted of killing Washington intern Chandra Levy, saying they can no longer prove their case in the 15-year-old slaying that thrust former congressman Gary Condit into the national spotlight. According to the statement, prosecutors concluded they can no longer prove the murder case against Guandique beyond a reasonable doubt, "based on recent unforeseen developments that were investigated over the past week." "[...] the government has had to concede the flaws in its ill-gotten conviction," the lawyers said, noting that Guandique had passed an FBI-administered lie detector test regarding his involvement. [...] Guandique was granted a new trial last year after doubts were raised about a jailhouse informant, Armando Morales, who was the key witness at Guandique's trial. In May, defense lawyers sought to take depositions from several women who said they had sexual relationships with Condit.