LOS ANGELES (Reuters) - The FBI on Monday released decades-old files on late pop singer Whitney Houston, detailing letters from obsessed fans and an alleged extortion attempt investigated by the bureau. The 128 pages from Houston's files posted online on the FBI's website showed one fan's attention-seeking letters but did not divulge any new insights into the troubled singer's personal life. Houston, known both for her soaring ballads and well chronicled history of drug abuse, was found dead last year in a Beverly Hills hotel bathtub. She was 48. ...