According to sources the Canadian born suspect shouted "Allahu Akbar" before stabbing a police officer in the neck at Bishop International Airport on Wednesday.
The streets of Paris were the site of violence Thursday night, when a gunman opened fire on a parked police van, killing one officer and wounding two more.
Law enforcement has taken into custody Ahmad Khan Rahami, the man wanted in connection to the weekend bombings in New York City and Seaside Park, New Jersey.
Three people were killed and more than 100 injured on Monday afternoon when two explosions went off near the finish line of the Boston Marathon. Rescue organizations have gathered to help and at the the tragic scene, but how can you help?
The Huffington Post has put together a helpful list of ways: