USA - Al-Zawahri, has threatened the United States if the execution of Dzhokhar Tsarnaev goes ahead

The leader of Al-Qaeda, Al-Zawahri, has threatened the United States with "grave consequences" if the execution of Boston Marathon bomber, Dzhokhar Tsarnaev, or any other Muslim prisioner goes ahead. In a new video, Al-Zawhri makes threats against America if the death sentence is carried out on the 22-year-old. Tsarnaev was found guilty last year of killing 3 people and injuring more than 260 others when he alongside his brother planted explosives at the finish line of the Boston Marathon in 2013. Al-Zawahiri, who was known as Osama Bin Laden's right-hand man, sits on America's 'Most Wanted' terrorist's list with a US $25million bounty on his head. He has been credited as the brains behind the 9/11 attacks and those on the London transport system in 2005. Tsarnaev is being held at the "Supermax" high-security prison in Florence, Colorado, while his attorneys appeal his death sentence. Legal wrangling over Tsarnaev's fate could play out for years or even decades. Just three of the 74 people sentenced to death in the United States for federal crimes since 1998 have been executed.