(CNN) — After weeks of searching vast swaths of ocean, investigators now have their “most promising” lead yet in finding Malaysia Airlines Flight 370.
A pinger locator in the Indian Ocean has detected signals consistent with those sent by a flight data recorder and a cockpit voice recorder, the head of the Australian agency coordinating search operations said Monday.
The sounds were heard at a depth of 4,500 meters (about 14,800 feet), retired Air Chief Marshal Angus Houston said.
“We’ve got a visual indication on a screen, and we’ve also got an audible signal. And the audible signal sounds to me just like an emergency locator beacon,” Houston said.
“We are encouraged that we are very close to where we need to be.”
But it could take days before officials can confirm whether the signals did indeed come from the plane, which fell off the radar on March 8 with 239 people on board.
“In very deep oceanic water, nothing happens fast,” Houston said. “I would ask all of you to treat this information cautiously and responsibly. … We haven’t found the aircraft yet.”
At least one investigator has described the search not as finding a needle in a haystack, but rather trying to find the haystack.
“It’s very exciting, very exciting,” forensic audio expert Paul Ginsberg said Monday. “I think we have finally found the haystack.”
And Malaysian authorities are hopeful there will be a positive development in the next few days, if not hours, acting Transportation Minister Hishammuddin Hussein told reporters Monday.
But some relatives of those on board haven’t lost hope, despite Monday’s news of the promising signals.
“If the plane is there, it’s there. We can’t change it,” the husband of one passenger said. “But I am still hoping for a miracle to happen.”
But time could be running out in tracing the sounds. In a few hours or days, the pingers aboard the plane stop transmitting for good.
The batteries inside the beacons, which are designed to start sending signals when a plane crashes into water, last about 30 days after the devices are activated.
Monday marks the 31st day of the search.