Roger Goodell (David Goldman/AP)

Robert S. Mueller released the findings from a nearly four-month investigation into the NFL’s handling of the Ray Rice domestic violence incident on Thursday, backing Commissioner Roger Goodell and the league as well as admonishing it.

The investigation by the former FBI director was ordered by the league after a second video of an elevator incident in a casino last February showed the former Baltimore Ravens running back delivering a knockout punch to his then-fiancee and triggered a domestic violence crisis in the country’s most popular sport. Over the summer, Goodell had suspended Rice two games for the incident after seeing video of the couple fighting. The second video of the actual punch, obtained by TMZ, prompted Rice’s release by the Ravens and his suspension by the league, a suspension that was overturned on appeal. One of the central issues in the investigation was whether the NFL had received and seen the second video, after the Associated Press reported that it had been sent to and received by a woman at the league.

The report released by Mueller and his team runs 96 pages and here are five major takeaways:

1) This may seem like a whitewash to many, but Mueller and his investigators “found no evidence that anyone at the NFL had or saw the in-elevator video before it was publicly shown. We also found no evidence that a woman at the NFL acknowledged receipt of that video in a voicemail message on April 9, 2014. ” Investigators spoke with 200 people and combed through a mountain of forensic evidence that included nearly 2 million phone calls and Mueller addressed his independence in an appendix to the report:

The League asked me to conduct an independent investigation concerning the Rice matter. The NFL did not direct, oversee, or otherwise manage or influence our independent investigation in any manner, and we did not report to the NFL during our investigation or on the results of our investigation. Instead, as explained in the report, the NFL authorized John Mara, owner of the New York Giants, and Art Rooney, owner of the Pittsburgh Steelers, to act as our points of contact to assist with our access to the League, its personnel and information, and other League resources necessary to complete the investigation.

As requested by the League, and as they specifically agreed, Rooney and Mara did not conduct, direct, influence, or otherwise manage our investigation in any manner.

We had sole discretion to employ investigative resources, techniques, and processes that we deemed appropriate in order to complete our investigation and to issue our report

2) A number of people wondered when the second video was released why the NFL needed to see it to determine adequate punishment for Rice in the summer. The report concludes “there was substantial information about the incident — even without the in-elevator video — indicating the need for a more thorough investigation. The NFL should have done more with the information it had, and should have taken additional steps to obtain all available information about the February 15 incident.”

3) The report is unlikely to be well received by advocacy groups that clamored for the firing of Goodell as the league’s domestic violence problem spiraled into a crisis in early September. Ultraviolet, which describes itself as “an online community of over 550,000 women and men who want to take collective action to expose and fight sexism in the public sector, private sector and the media,” reacted swiftly to the report’s contents.

“Mueller’s report doesn’t change the facts,” UltraViolet co-founder Nita Chaudhary wrote in an email to The Post, “Under Goodell’s tenure, more than 55 cases of domestic abuse went unanswered. The NFL has a domestic abuse problem, and it simply doesn’t have the leadership to fix it. It’s clear from this report that Goodell’s NFL took no initiative to uncover the facts in this case— a continuation of Goodell’s long record of ignoring this issue. It’s time to take domestic violence out of the NFL, but first Goodell must go.”

4) Goodell is extremely unlikely to go anywhere, but a great deal of damage remains to be repaired and he is the man who will be charged with doing it. His job was never really in danger and the men who pay his salary backed him yet again Thursday.

“Mr. Mueller concludes that the league should have conducted a more substantial independent investigation of this matter and he has made six recommendations,” Mara and Rooney said in a statement. “This morning, we spoke to Commissioner Goodell about these recommendations. We want to review them and understand them in greater detail. We look forward to moving forward on this.

“This matter has tarnished the reputation of the NFL due to our failure to hand out proper punishments. It has been a wake-up call to all involved and we expect the changes that have been made will lead to improvements in how any similar issues are handled in the future.

“It is clear to us that Commissioner Goodell was forthright in the statements he made to the owners about this matter and we have every confidence that Roger Goodell is the right person to lead the league as we move forward.”

5) So, if it seems like nothing changes, that’s because … nothing changes.

The NFL, as Goodell has repeatedly acknowledged both personally and as the man in charge, should have done better in handling the Rice incident. Goodell and the league blasely underestimated the message that was sent to women when Goodell initially suspended Rice only two games and when Goodell so hamhandedly handled a press conference last fall. But bad public relations isn’t against the law and the Mueller report, sanctioned by the league, found no legal malfeasance.

As Mara and Rooney hope, the league moves forward, as it began to do in December when, a month ahead of the report’s release, Goodell announced the creation of a nine-owner panel to oversee a player conduct policy designed to prevent domestic violence issues in the future and to punish players consistently when incidents occur.