The FBI is looking at an 'odd bit of buried foam' as possible evidence in the cold case investigation into 1971 Seattle plane hijacker D.B. Cooper, according to private investigators. The potential evidence was handed over to authorities last week by the team of sleuths who believe the foam made up a part of Cooper's parachute backpack. Cooper, one of the 20th century's most compelling masterminds, hijacked a Boeing 727 at Seattle-Tacoma airport in 1971 and held its crew and passengers hostage with a bomb. Once his demand of $200,000 cash - the equivalent of $1,213,226 today - was reached and transferred onto the plane, Cooper had the crew take off before he parachuted out over the dense Pacific Northwest woods and disappeared. The discovery of the foam comes just weeks after the FBI uncovered what is believed to be part of Cooper's parachute strap, which private investigators - led by TV and film executive Thomas Colbert - claim could lead authorities to his stolen fortune.