A composite image  shows what is believed to be the two Iranian passengers who used stolen passports to board a Malaysia Airlines flight that subsequently went missing. One of the two was seeking to relocate to Germany, Malaysian police said, while the other  was believed to be travelling to Sweden, Swedish police said. (Azhar Rahim/EPA)

In the first few days after Malaysia Airlines Flight MH370 disappeared over the South China Sea, the frustrating lack of clues led many to focus on one strange detail: Two people on board the flight were found to have been flying on stolen passports. The implication was clear.

New developments, however, suggest that the stolen passports were not a sign of terrorism. Instead, they appear to have been a byproduct of the hidden world of modern migration.

So what might have happened? Let's try and answer the big questions.

Who were the men traveling on stolen passports?

Malaysian authorities today announced that the two men on the flight were Pouria Nour Mohammad Mehrdad, 19, and Delavar Seyed Mohammad Reza, 29, two Iranian citizens who boarded the flight with stolen Austrian and Italian documents.

Were these men trying to get out of Iran?

We can't say for sure, but tens of thousands of people emigrate from Iran every year. A sizable number are asylum seekers, under threat for their political activities, religious or ethnic background or their sexual orientation. While the United States used to be a top destination, tough immigration policies have made European countries such as the United Kingdom, Germany, Austria, Denmark and Sweden more favorable destinations.

Mehrdad is believed to have been attempting to emigrate to Germany: His mother was waiting for him in Frankfurt, and contacted Interpol when he didn't arrive. A Facebook page that appears to belong to him says he was feeling "excited" and had messages from friends wishing him a good trip. While Reza's final destination isn't confirmed, it seems likely he was also attempting to migrate.

But why go to Malaysia if they were trying to get to Europe?

The Malaysia part, of course, seems a little odd. Why would an Iranian hoping to migrate to Europe head thousands of miles in the wrong direction? While there are no accurate statistics about trends in how Iranians go about reaching their destination country, Thailand and Malaysia are among the countries with the most lax rules about allowing entry to Iranian nationals, and they are a relatively cheap journey. The pair also appeared to have a friend in Malaysia who they stayed with, according to ABC News.

And why book a flight to Amsterdam via Beijing?

Once in Malaysia, ABC News reports that the pair arranged over the phone to travel to Europe with an Iranian man known as "Mr. Ali," booking flights from Kuala Lumpur to Amsterdam via Beijing. Once in Amsterdam, their paths diverged, with one man going to Copenhagen and another to Frankfurt.

While Beijing looks like another unusual detour, the logic seems to be quite simple: Money. The Financial Times has reported that "Mr. Ali" had contacted Benjaporn Krutnait, owner of travel agency Grand Horizon Travel in Thailand, to book cheap flights to Europe for the two men on March 1. When Mr. Ali did not get back in contact in time, the flight reservations were lost, and she had to re-book the Malaysia Airlines flight through Beijing. The flight was chosen as it was the cheapest flight to Europe available.

So why did they need fake passports?

While it was easy to get into Malaysia on their Iranian passport, Europe is a whole other kettle of fish. The pair needed E.U. passports to get on the plane.

And where did they get them?

It isn't totally clear where they got the passports, but one Iranian friend reportedly told the BBC's Johnathan Head that they bought them in Iran and paid $10,000 each for them. Another possibility is Thailand, where the passports were stolen. Malaysian authorities have said that at least one of the men had arrived in Malaysia from Phuket, and according to the New York Times, U.S. law enforcement officials are said to be investigating a "so-called passport ring" on the Thai island.

Is it really that easy to get on a flight with a stolen passport?

The pair reportedly altered their appearance to look like the men in their passport pictures, and while the two passports were reported as stolen and put on Interpol's database of stolen documents, Malaysian authorities never checked that database.

According to the Times, the database, which has 40 million documents in it, is only regularly used by the United States, United Kingdom  and United Arab Emirates. Even if the passports were discovered in Europe, the pair would likely have been able to apply for asylum, and they may well have had it granted: 52.8 percent of Iranian asylum seekers were granted either asylum or refugee protection in accordance with the Geneva Convention in 2013, according to the German Federal Office for Migration and Refugees.

Does this rule out terrorism?

“The more information we get, the more we are inclined to conclude it is not a terrorist incident,” Ronald Noble, secretary general of the international police agency Interpol, told reporters today.

At this point, however, nothing can be completely ruled out.

Jason Rezaian in Tehran and Stephanie Kirchner in Berlin contributed to this post.