WASHINGTON (AP) — Federal investigators have now connected the hacking of Sony Pictures Entertainment Inc. to North Korea, a U.S. official said Wednesday, though it remained unclear how the federal government would respond to a break-in that exposed sensitive documents and ultimately led to terrorist threats against moviegoers. A security professional with knowledge of the breach also said investigators had strong circumstantial evidence and technical commonalities pointing to North Korea. [...] Wednesday, the Obama administration had been saying it was not immediately clear who might have been responsible for the computer break-in. [...] a singular IP address in Bolivia seemed to match the server used in the DarkSeoul attack, while two others led to Singapore and Thailand. Because North Korea is highly controlled in its connection to the outside world, links back to it are almost always to proxies or presumed connections to the country, the security professional said.