PITTSBURGH — The murky, debris-laden waters of the Monongahela River foiled even the new technology that searchers were using to try to lay to rest rumors about the crash of a World War II-era bomber into the river.

Officials say 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. Since the plane was never recovered, stories and conspiracy theories about the aircraft and its cargo have spread, and some even suggest that the Army spirited away the wreckage.

An organization called the B-25 Recovery Group has been trying to get to the bottom of the matter for more than a decade. On Friday, searchers used sophisticated sonar and other electronic gear to identify targets, including what they believed to be one of the plane's propellers. On Saturday, divers from Marion Hill Associates searched the river but were unable to find anything because of poor visibility and debris littering the river bottom.

The search was called off and an official of the group said he was not sure how it would proceed in the future.