A lengthy 179-page affidavit [PDF] from the special agent in charge of the investigation gives an extensive rundown of how the attacks were tracking back to Hyok, his hacking group, and eventually the North Korean government.
"North Korea has demonstrated a pattern of disruptive and harmful cyber activity that is inconsistent with the growing consensus on what constitutes responsible state behavior in cyberspace", the Treasury said in a statement.
Park, who USA officials believe is now in North Korea, faces charges that include conspiracy to commit wire fraud.
The Justice Department announced the charges against Pak Jin-hyok, a member of the North Korean spy agency, on Thursday afternoon. Sony was responsible for The Interview, a fictionalized assassination of North Korea's leader. The depiction caused officials to complain to the United Nations and resulted in the state media of the isolated nation warning of "merciless retaliation".
"It's been four years since North Korea's petty little despot hacked Sony Pictures because he didn't like a movie that a free and open society produced".
In one attack, an email sent to a victim from Facebook alerting them to the fact that their account had been accessed from a different IP address was grabbed by the hackers and then resent with the hyperlink within the email changed from Facebook's website to a domain that they controlled.More news: Emirates jet lands in NY with 10 ill passengers
The U.S. Treasury Department has imposed sanctions against Park and the Chinese-based front company he worked for, Chosun Expo.
No North Korean government officials were referenced in the complaint by name, though it does allege the government sponsored the attacks.
They named one of the group - called the Lazarus Group by security companies fighting to combat its actions - and put his name, Park Jin Hyok, and face on an FBI Wanted poster, adding that he is now considered a fugitive from justice. There has been no communication between the USA and North Korean government about a possible extradition, the official said.
The 34-year-old worked "on behalf of the government of North Korea or the Workers' Party of Korea", according to U.S. authorities.
The Associated Press reported that a North Korean who is believed to have operated out of China will be among those charged.
The DOJ has charged hackers in China, Iran and Russian Federation aiming to dissuade foreign powers from accommodating those who would attack US corporations.
Thursday's charges come on the same day that President Donald Trump praised the North Korean leader.