PITTSBURGH (AP) _ Divers and scientists plan to spend the weekend in Pittsburgh's Monongahela River, using new technology to search the murky waters for a mystery a half-century old: the remnants of a World War II-era bomber that crashed into the river during the Cold War.

The official story is that the B-25 bomber ran out of fuel on Jan. 31, 1956, when it was on its way to Harrisburg, and plunged into the river, narrowly missing a busy Pittsburgh bridge.

The crew of six initially survived the impact, but two members then disappeared. Since the plane was never recovered, stories and conspiracy theories have spread.

Some have said the plane was secretly removed by the Army under cover of darkness and whisked away to hide its secret cargo. Depending on who you ask, that can be anything from Cold War secrets to UFO parts to nuclear bomb components.

Those searching for the missing bomber, including the B-25 Recovery Group's operations director, Bob Shema, brush off such theories. Group member John Uldrich says censored portions of the official report likely refer to whoever was to blame for the plane going down on its way from Nevada.

Now, the group is using high-tech sonar scanners, metal detectors, remote-controlled cameras and ground-penetrating radar to try to find the missing plane. Experts say this equipment wasn't available in the 1990s, the last time explorers hunted for the plane.

Shema said the chances of finding the whole bomber are slim since decades of exposure to the river's polluted waters and barge traffic overhead would have dissolved its aluminum exterior. Instead, Shema said the group is looking for things that would have survived, including engine blocks, landing gear or even cockpit windows.