False alarms, swirling rumours and contradictory statements have made the wait all the more agonising for the families of the 239 people on board the missing Malaysia Airlines flight MH370. As the search dragged into its fifth day, here are some of the key areas of confusion:
Did the plane veer off course?
• Malaysia's air force chief on Sunday raised the possibility that the plane inexplicably turned back after taking off from Kuala Lumpur en route to Beijing a day earlier.
• General Rodzali Daud said the theory was "corroborated by civil radar", without giving further details.
• Late Tuesday, Rodzali was quoted by a Malay-language paper as saying the jet had been tracked hundreds of miles from its intended flight path, over the Strait of Malacca off western Malaysia.
• Vietnam had initially said the plane was approaching its airspace when it vanished from radar screens.
• Rodzali has since insisted that he did not make the comments attributed to him by the Berita Harian newspaper, and the report was "inaccurate and incorrect".
• The search on Wednesday swung even further up Malaysia's west coast, towards the Andaman Sea, but officials gave no indication there was a firm reason to expand the search other than its failure to bear fruit so far.
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Full coverage: Missing Malaysian Airline flight MH370
What time did it happen?
• Officials say contact with the aircraft was lost at around 1:30 am Malaysian time (1730 GMT Friday), about an hour after take-off from Kuala Lumpur International Airport. Initially, Malaysia Airlines had put the last contact time at 2:40 am.
• The timing of 1:30 am would place the plane between Malaysia and Vietnam, where Vietnamese air traffic control and flight-tracking websites say the plane vanished off radar.
• The later time of 2:40 am could suggest the plane had indeed veered radically off-course. Despite the Malaysian air force chief's denial of the Berita Harian report, that theory has gained credence given the expanded search area off Malaysia's west coast.
Where did it happen?
• The search began in the South China Sea and Gulf of Thailand, on the approach to Vietnamese airspace.
• Since then, Malaysian authorities have widened the search radius several times as well as shifting its focus, fuelling accusations of official bungling and a slow-footed response.
• Authorities have not said whether they have any firm indications that the plane might be in the Andaman Sea.
• Vietnam suspended its air search and scaled back a sea search on Wednesday -- awaiting clarification from Malaysia about the potential new direction for the search, which involves dozens of ships and aircraft from several countries including China and the United States.
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Where is the debris?
• There have been several false alarms linked to debris spotted in busy shipping lanes in Southeast Asian waters.
• Large oil slicks found by Vietnamese planes on Saturday yielded no trace of the plane; nor did debris found Sunday near Tho Chu island, part of a small archipelago off southwest Vietnam.
• Malaysia sent ships to investigate a sighting of a possible life raft on Monday, but a Vietnamese vessel that got there first found only flotsam.
• Chemical analysis by Malaysia on Monday found no link between oil found at sea and the missing plane.
Conflicting information on plane's course 'pretty chaotic', says China
The passport mystery
• Revelations that two of the passengers were travelling on stolen EU passports fuelled early speculation that the plane was the victim of a terrorist attack.
• Malaysia's national news agency Bernama on Sunday quoted Home Minister Zahid Hamidi as saying the two suspect passengers had "Asian features", without elaborating.
• It emerged on Tuesday that the pair appear to be Iranian illegal immigrants who were seeking a new life in Europe.
The mystery of ringing phones
• Chinese media have reported that relatives have heard ringing tones when trying to call their missing loved ones' mobile phones.
• The accounts of some passengers on Chinese messaging tool QQ show they had been online, other reports say, although the operator says that failure to shut the software down properly can give that impression.
• Alfred Siew, a Singapore-based technology commentator, admits it is a "mystery", but said the matter could be merely due to a network error affecting some phones.
600,000 scan satellite images for clues to jet
• Azharuddin Abdul Rahman, head of Malaysia's Department of Civil Aviation, said Monday that five passengers who had purchased tickets and checked baggage did not make the flight.
• He told journalists their luggage was removed from the plane, per standard procedure, when routine checks indicated the five passengers had not boarded before take-off.
• But Malaysia's national police chief Khalid Abu Bakhar insisted Tuesday that all passengers who booked the flight did board in the end.
• However, muddying things further, Malaysia Airlines issued a statement hours later saying there were indeed four passengers who had valid bookings but did not check-in for the flight.