Will I have to work on Saturdays? http://cliphunter.in.net/ www.cliphunter.com  Government investigators say Islamist radicalism was Mr. Tsarnaev’s motive in planting explosives near the finish line of the race. He frequented jihadi websites, authorities said, and he and his brother built their pressure-cooker bombs with the help of al Qaeda’s online magazine Inspire, which published an article titled “How to Build a Bomb in the Kitchen of Your Mom.”