Speaking to NBC's Brian Williams, Mr Cook noted that key components in Apple products such as the iPhone were already manufactured in the US, but were then shipped out to be assembled.

BBC: Tim Cook

Mr. Tsarnaev's ability to speak Russian would have allowed him to be something of a "native guide for Kazakhs far from home, " said Brian Glyn Williams, a professor of Islamic history at the university who once advised Mr. Tsarnaev on a paper he was writing on Chechnya.

WSJ: Heritage Linked Boston Suspect, Students