Three things you must know this week…

1) Two explosions rocked the finish line of the Boston Marathon Monday, killing three and seriously injuring another 170. Video footage showed two suspects leaving the bombs and fleeing the scene. They were identified Friday as Tamerlan, 26, and Dzhokhar Tzarnaev, 19, who are believed to be on Chechnyan origin but have lived in the US for ten years. Thursday evening, the brothers shot and killed a police officer on the Massachusetts Institute of Technology campus before fleeing in a stolen car. A chase and firefight occurred, in which Tamerlan Tzarnaev was killed. On Friday afternoon, the city of Boston was in lockdown as the Boston police hunt for Dzhokhar, who was discovered wounded in a residential area. An additional bomb was discovered and dismantled Friday morning. An unidentified associate is also being sought.

2) In other US news, a bill which would require background checks when purchasing firearms online or at gun shows was defeated within Senate Thursday. Hopes were high as the bill was a compromise proposal drafted by members of both parties, and was supported by the White House as well as 90 per cent of the American public. The bill was defeated 54-46, with a majority of Republican senators moving to vote against, including ten who had previously supported the bill but changed their views in the 48 hours leading up to the vote. Newtown families, as well as numerous others affected by gun violence looked on from the visitors gallery as the measure fell. President Obama delivered a speech later that same day, shaming members of Congress for caving to the gun lobby and declaring this only round one in the fight for reform.

3) Violence in Bahrain flared as the country prepares for the Formula One Grand Prix, set to take place on Sunday. Main opposition group al-Wefaq and other pro-democracy groups are calling for the race to be cancelled due to the poor human rights conditions and slow progress of reform in the kingdom. The Crown Prince of Bahrain argued on Thursday that though Bahrain is still not perfect, it has seen significant improvements in the last year. Additionally, he claims the race is supported by 77% of the population and will bring financial benefits to 90% of the country. FIA president Jean Todt released a statement confirming the race was still on and praising the ability of the Grand Prix to bring people together.