(CNN) - The four acoustic pings at the center of the search for Malaysia Airlines Flight 370 for the past seven weeks are no longer believed to have come from the plane's black boxes, a U.S. Navy official told CNN.
The acknowledgment came Wednesday as searchers wrapped up the first phase of their effort, having scanned 329 square miles of southern Indian Ocean floor without finding any wreckage from the Boeing 777-200.
Authorities now almost universally believe the pings did not come from the onboard data or cockpit voice recorders, but instead came from some other man-made source unrelated to the jetliner that disappeared on March 8, according to Michael Dean, the Navy's deputy director of ocean engineering.
If the pings had come from the recorders, searchers would have found them, he said.
Dean said "yes" when asked if other countries involved in the search had reached the same conclusions.