(CNN) -- The possibility of closure for relatives of the passengers and crew of Malaysia Airlines Flight 370 may have emerged from the depths of the southern Indian Ocean on Saturday in the form of an unconfirmed pulse signal.
After an agonizing month of waiting, however, the 37.5 kHz signal detected by a Chinese patrol ship could be another siren song in the mysterious disappearance of and search for the Boeing 777 carrying 227 passengers and 12 crew members.
The signal reported "is the standard beacon frequency" for the plane's cockpit voice recorder and the flight data recorder, said Anish Patel, president of pinger manufacturer Dukane Seacom. Other experts cautioned that no confirmation had been made that the signal was linked to the missing plane.
"I don't believe it," Jack Song, whose sister was on the flight, told CNN. "There's no piece of debris, so how can you find the black box? So you can just wait for more news tomorrow. Maybe it'll be another mistake."
His elder sister was returning from a holiday. Her connecting flight was through Kuala Lumpur, Malaysia. After news of the missing flight, Song took leave from his job and went to Beijing in search of answers. Song and eight other passengers' relatives had been gathering in a Beijing hotel room and designating themselves a media committee.
They protested in front of the Malaysian Embassy in China and shared with the media a video of meetings with Malaysian officials. They have expressed their dissatisfaction with the Malaysian government's explanation that satellite data indicated the plane most likely crashed in the Indian Ocean.
Tom Wood, a brother of American passenger Philip Wood, said his family would have no comment until authorities provide concrete evidence.
"We don't want to give any reaction right now," he told CNN on Saturday. "We want something solid before commenting on anything. When they know something for sure, then I myself, my brother, my parents will be happy to talk."
The Wood family will not say goodbye without seeing something that shows that Philip Wood died. The IBM executive, who was headed back to Beijing before taking a new assignment in Malaysia, was one of three Americans on Flight 370.
In a text message in Kuala Lumpur, Jiang Hui, a Chinese relative of a passenger, responded with caution: "THERE IS NO CONFIRMATION, AND WE ARE ALL WAITING PATIENTLY."
The majority of the passengers were from China. Relatives of the 154 Chinese passengers who were aboard Flight 370 have been oscillating between grief and visceral anger as the search for the plane carrying their loved ones continues.
The possible breakthrough in the search was reported by the state news agency Xinhua, which said the Chinese patrol ship Saturday detected the pulse signal used by so-called black boxes.
But the pulse signal has not been confirmed, China's Maritime Search and Rescue Center reported, according to China Communications News, which is the Ministry of Transport's official newspaper.
Also found Saturday -- spotted by a Chinese air force search plane -- were white objects floating near the search area, about 1,700 miles (2,700 kilometers) from Perth, Australia, Xinhua said.
Flight 370 vanished on March 8 while flying from Kuala Lumpur to Beijing. Authorities from around the world have been searching the Indian Ocean for the missing plane but have so far found nothing, leaving families of the passengers with unanswered questions.
Some have criticized the response and accused Malaysian officials of giving them confusing, conflicting information.
On Monday, dozens of Chinese relatives visited a Kuala Lumpur temple. They chanted, lit candles and meditated.
"Chinese are kindhearted people," said Hui, the families' designated representative. "But we can clearly distinguish between the good and evil. We will never forgive for covering the truth from us and the criminal who delayed the rescue mission."
Hui asked Malaysia to apologize for announcing on March 24 that the plane had crashed, despite the lack of any "direct evidence."
On March 24, Malaysia Airlines and Malaysian Prime Minister Najib Razak said that the plane had gone down in the southern Indian Ocean and that there were no survivors.
But nothing related to the flight has been found, and that has deepened the pain for some.
CNN's Pauline Chiou, Ingrid Formanek, Judy Kwon, Sara Sidner and Dana Ford contributed to this report.