North Korea never Intervened in the 'Interview' Hacking Incident?

A claim  that an ex-IT engineer hacked Sony Motion Pictures
regarding its comedy American film 'Interview' was brought up.
'New York Post' reported that Norse Crop., 
a cyber security firm, delivered to the FBI
an analysis that 6 ex-workers of Sony and not North Korea hacked Sony.

Norse Corporation clarified that "we have concluded that North Korea is
not behind the hacking incident" in the report.
In addition, it also criticized the U.S. FBI's official report claiming
North Korea as be responsible for this hacking incident that
"Finding out who's behind the cyber attack
just a few days after it happened is almost unheard of"

In the meantime, 'Interview' is a movie about the assassination of Kim, Jung-eun,
the leader of North Korea and the chairman of the National Defense Committee.
Its ticket sales were over 15 million dollars online on the first weekend after its release.
Such box office profit is the highest among all of Sony movies distributed online..
Also, America refused North Korea's
offer to solve the 'Sony hacking incident' together.