FBI Director James Comey gave a speech yesterday and doubled down on the FBI’s decision to name North Korea as the source of the late November cyber attack on Sony Pictures.

According to the FBI, the hackers made some sloppy mistakes. They often used a proxy system to hide their real location but in a few cases signed into a Sony server and posted online without concealing their location. The FBI says their IP address is known to be exclusively used by North Korea.

Kim Zetter, a reporter at Wired and author of “Countdown to Zero Day: Stuxnet and the Launch of the World’s First Digital Weapon,” isn’t convinced North Korea is to blame for the attack.

“We still don’t have all of the evidence and all of the information that’s backing his strong claim there,” Zetter says.

A few things that give Zetter pause:

• We don’t know what this IP address is or what it’s connected to.

• The FBI is saying that this IP address is exclusively used by North Korea. How do we know that?

• Initial communication from the hackers never mentioned the movie “The Interview.” It appeared to be an extortion attempt to get money out of Sony.

The FBI has requested that the government  unclassify information related to the case, so that more can be publicly disclosed.

As for Sony? They’re still struggling and are working on replacing equipment.