National Intelligence Director James Clapper said it appears a "non-state actor" may have been responsible for last week's massive cyber attack.
The attack briefly blocked access to websites like Twitter, Facebook and the New York Times.
Tuesday, Clapper spoke with "CBS This Morning" co-host Charlie Rose and said investigators are still gathering a lot of data, but it appears a non-state actor is to blame.
WATCH | James Clapper at the Council on Foreign Relations in New York
Last Friday, the cyber attacks repeatedly disrupted popular websites across the United States.
Members of the hacker group called "New World Hackers" initially claimed responsibility for the attack, but those claims were never verified.
The group claimed an organized network of "zombie" computers called botnets threw 1.2 terabits of data per second at Dyn Inc., which provides services to a significant number of America's Fortune 500 companies.
What happened last Friday is known as a Distributed Denial of Service (DDoS) attack. This type of attack basically attempts to make online services unavailable by overwhelming a site with a massive amount of traffic from multiple sources.
WATCH | For more news you need, watch our 60 Second Circa.