The Boston Marathon bombing is being considered an act of terror by the White House and other officials, but so far no direct confirmations have been made about a possible motive or suspects in the attack, which has left three people conformed dead and hundreds more injured.

According to Slate.com, a surprise attack on the marathon has been mentioned before to police, including in a 2003 Massachusetts State Police report that warned of an attack on the event since there are a number of people at the finish line and it involves live television and celebrations. The report was mentioned in the Boston globe and "warned that the [Boston] Marathon could be a 'possible prime terrorist target' because it involves such a large number of runners and spectators, draws a live worldwide television audience, [and] coincides with the Patriots Day holiday in Boston."

Prior to that report, the idea also was made by an author named Tom Lonergan, who published "Heartbreak Hill: The Boston Marathon Thriller" that took place in the world of long distance running and involved terrorism, police and the marathon.

Many on social media also spoke about the British film "Four Lions," which is an intelligent and dark comedy about four terrorists in England who attempt to target the London Marathon. The film takes a look at the world of terrorism from a different angle and the main characters are followed through training and many hijinks as they try to become bombers.

The friends eventually plan to target the London Marathon and are shown using costumes to disguise themselves. The terrorists eventually carry out the attack. Here is a link to the film's page. The short description from Wikipedia is: "The film is a jihad satire following a group of homegrown terrorist jihadis from Sheffield, South Yorkshire, England."

Here is the book synopsis:

The trouble with most terrorists is they think too small. This is the message Boston police receive days before fifteen thousand runners and two and a half million spectators descend on the city for the marathon. Even bin Laden only killed thousands. What if the target was larger? What if millions were at risk?

Sgt. Mike Quinn, Vietnam vet, homicide detective and addicted marathoner, is called in to help when domestic terrorists, looking to piggy-back onto the World Trade Center disaster, threaten a race day bloodbath. How real is the threat? On Sunday, October 28, 2001, six weeks after the attack on the World Trade Center, the Boston Globe printed a call-to-arms by Rocky Suhayda, the chairman of the American Nazi Party: "if we were one-tenth as serious as the bin Laden terrorists, we just might start getting somewhere."

Quinn is a divorced, forty-something year old history buff, who loves his city and its marathon. He's run the race six times. And when marathon director Ronnie Silk is killed, Quinn is assigned to protect Raven, the red hot rock 'n roll diva and the marathon's first-ever celebrity entrant. Raven is a magnet for trouble. And Quinn scrambles to keep up with her during the final miles of the race while trying to flush out the maniac terrorists.