It's the story that has the entire world baffled and horrified. What happened to Malaysia Airlines Flight 370?

At 12:41 a.m. Saturday, March 8, a Boeing 777-200ER carrying 227 passengers and 12 crew members took flight from the Malaysian capital of Kuala Lumpur. The plane was scheduled to land in Beijing, China at 6:30 that morning. Except it never arrived.

At some point during its 2,700-mile (4,350-kilometer) long flight, air traffic controllers lost track of the plane. It was last made contact with somewhere between Malaysia and Vietnam, at which point it stopping sending transponder codes.

It is unknown what happened at that point. The pilot never indicated any issues with the flight. No distress signal was sent. Search teams scouted the area for any sign of a wreckage, and found nothing. The plane just seemed to simply vanish.

More than four days later, Flight 370 still remains nowhere to be found, although there have been minor developments. Malaysian civil aviation authorities and military reported Tuesday that an unidentified plane had been detected somewhere near the Strait of Malacca, a shipping lane located on the western coast of Malaysia.

This confirmed suspicions that the plane may have turned back at some point.

The new reports, however, may have only served to complicate matters even further. If the plane was indeed Flight 370, as it seemed likely to be, then it would have been flying hundreds of miles off its intended course. Not only that, but officials are uncertain which direction the plane was flying in, making search efforts even more difficult than before.

"At this stage in the investigation and search and rescue, I would have expected to see by now a much more defined understanding of what the route was, where the plane was headed and a narrowing of the search consequent upon that," said CNN aviation expert Richard Quest.

Still, multiple countries in the area are aiding in the search for debris or any other sign of a crash. So far nothing found has been determined to be related to the aircraft. An oil slick found in the area raised hopes briefly, before turning out to be from a local cargo ship.

As they search, family members of the 239 people onboard have endured an agonizing wait to hear any news at all concerning their lost loved ones. The plane contained passengers of several nationalities, including 4 United States citizens, and over 150 Chinese and Taiwanese citizens. Five of the passengers were under five years of age.

Frustration among friends and family members has understandably risen. They're upset and they want answers.

"Time's flying and you need to search for the people!" said one sobbing man, as reported by CNN. He demanded to know why he could hear his son's cell phone ring when called it. And he wasn't the only one. Several people reported being able to connect to the passenger's mobile numbers.

Officials seem to be just as perplexed by the situation. Some experts have suggested that it's a result of a call-forwarding configuration, but their explanation did little to satisfy angry and grief stricken relatives.

Indeed, it seems there are far more question than there are answers. How could this have happened? In this day and age, with advanced radar technology, how could a commercial jet just up and disappear with no trace?

According to an article by The New York Times, the idea of a plane falling completely off the radar isn't completely beyond comprehension. Radar coverage can be limited, particularly over water. In such cases, pilots are required to radio in their position regularly. It could have been during one these periods that Flight 370 malfunctioned.

As the question of why the pilot wouldn't have radio in for help, apparently pilots put that on the bottom of a priority list. Air traffic controllers can often do little to help a plane in imminent danger. It's far more sensible to invest attention to piloting and navigating the aircraft.

That, of course, doesn't answer the question of why the plane went down... if it even went down at all.

One theory was that the plane may have had a severe explosion and disintegrated midflight. This would explain why no plane debris can be found.

This conclusion is quickly loosing steam due to the later detection of the plane off the Strait of Malacca. At the time of detection the plane was not sending out transponder signals, leading some to believe the plane had a malfunction that caused it to lose power. It would also explain why the plane was flying in the wrong direction.

Other possible explanations include hijacking or pilot error. In the case of the former, officials were alerted to two Iranian passengers carrying stolen passports. Eighteen-year-old Pouri Nourmohammadi and 29-year-old Delavar Seyed Mohammad Reza were suspected to be involved in a possible hijacking. However, it was soon concluded that the two did not have any links to known terrorist groups, and that Nourmohammadi was likely seeking asylum in Germany. Nourmohammadi's mother was waiting for him there, and contacted the airport when he did not arrive.

Whatever the cause was, it's clear that the priority is finding the aircraft before all else. Something made all the more difficult by the lack of substantial evidence or leads.

"I always like to think that we need to start by finding the haystack, and then we can look for the bits of the needle in that haystack," said oceanographer David Gallo to CBS. "In this case the haystack is huge because we just don't have the clues."