The investigation was led by NBC Universal's general counsel Kim Harris, and focussed on Lauer's behaviour in the workplace and the complaints from four women who came forward in late November a year ago.
Lauer, 60, was sacked in November after the accusation of sexual misconduct surfaced, stripping the broadcast network of one of its best-known stars. She determined there were no complaints about Lauer prior to the one that led to his firing-three additional women came forward after his termination.
NBC released its investigation into "Today" show host Matt Lauer's history of workplace harassment on Wednesday, concluding that there was "no evidence" that any senior executives at the network were aware of complaints about Lauer until November.
The report, a summary of which was released Wednesday morning, also determined that there isn't believed to be a systemic culture of inappropriate behavior and sexual harassment at NBC News.
NBC leadership were also unaware that Lauer "had engaged in sexual activity with other employees", the report says.
During her past year on the "Today" show, in 2012, Lauer's co-host Ann Curry said she approached two members of NBC's management team after an NBC female staffer told her she was "sexually harassed physically" by Lauer. "A number of girls additionally credibly described to the investigation crew being the topic of what they believed was a sexual overture from Lauer through which he complimented them on their look in sexually suggestive methods". What we can do is learn from it, and try to make it right.More news: Mormon church cutting ties with Boy Scouts
NBC said the work of its all-female investigative team was reviewed and approved by two outside firms. "The members of NBC News and Today show leadership at the time with whom we spoke denied having any such conversation with Curry". The manager agreed that the complainant would not be assigned to projects that required her to travel with Lauer, and the manager did not recall reporting the interaction to anyone else. He offered a seven-point plan for "a safer and more respectful environment", including more training for managers, mandatory workplace training, and "constant vigilance, monitoring and measuring progress". The button closed the door, but didn't lock it, the report said.
NBC News told employees Thursday that they can now raise workplace concerns to an outside law firm associated with trainers who have been conducting workshops for employees, as well as a new team that reports to NBCUniversal's legal department, not NBC News' human resources staffers.
An attorney who represented one of the women who came forward to NBC about Lauer's behavior said Thursday called for more to be done.
Curry told The Washington Post that a woman came to her in 2012 saying Lauer had sexually harassed her, and that she had warned management about him.
One particular detail that took on a life of its own when the story first broke was the infamous desk button in Lauer's office that reportedly locked the door from the inside. They also did not report the incidents to any member of leadership. To critics, the button seemed an alarmingly useful tool for predatory behavior, but NBC said it is "a commonly available feature in executive offices" and does not lock the door from the inside. But - stepping back from the investigation - that history also includes a time when people were not comfortable coming forward to voice complaints about repugnant behaviour.