LINDEN (AP) — The childhood friends killed for the first time less than three months after their high school graduation in 1984. Then they seemingly killed with impunity for the next 15 years, with one man making barroom boasts about their ability to make people disappear. By the time the hunting buddies were finally arrested in 1999, investigators say the notorious "Speed Freak Killers" killed as many as 20 people during a 15-year spree that terrorized California's rural Central Valley.