LOS ANGELES, Aug. 29 (Xinhua) -- U.S. authorities are running tests on items allegedly belonging to the infamous Zodiac killer, who had taunted police for more than a decade in Northern California, a report said Friday.

    The articles were given to the FBI by a Californian man who claimed his stepfather was the serial killer who had murdered five people and maybe some more in the San Francisco area in the 1960s and 1970s and thus inspired many Hollywood producers.

    The killer calling himself Zodiac sent to press a series of taunting letters with cryptograms related to his identity, challenging police's wisdom. Most of the cryptograms are yet to be solved.

    San Francisco Police Department marked the Zodiac killer's case "inactive" in 2004, but reopened it some time before March 2007.

    The man who claimed to be the stepson of the killer told FBI investigators that he found a black hood with a zodiac on it along with a knife stained with blood when going through his late stepfather's belongings, reported local TV station KTVU.