Mara said the team was "comfortable" retaining Brown, who was arrested in 2015 and suspended following the league's investigation into domestic violence allegations.
"When we made the decision to re-sign Josh back in (2016), we were certainly aware of the arrest," Mara said. "We were also aware of the allegations associated with that arrest and the fact that the charges were dropped within a couple of days after the arrest. Based on the facts and circumstances that we were aware of at that time, we were comfortable with our decision to re-sign him. Nothing has happened in the meantime to make us question that decision. This is an issue, domestic violence, that we take very seriously here."
After finding out about Brown's arrest in May 2015, the NFL became aware of a court statement filed by Brown's wife alleging previous altercations with her husband. Brown's wife declined to speak to league investigators about the alleged incidents and law enforcement officials declined requests from the NFL for information.
The NFL concluded that Brown violated the league's personal-conduct policy based on evidence provided in the police report from his arrest, which included statements provided by Brown's wife to police. A hearing officer upheld the suspension on appeal from Brown and the NFL Players Association.
"We were certainly aware at the time that there were allegations of numerous incidents," Mara said Wednesday in his first comments on the allegations. "Based, again, on the facts and circumstances that we are aware of, we were comfortable with our decision to sign him."
Mara said domestic violence is not a "black and white" issue.
"We attempted to make an informed decision here, we will live with the results of that decision and we move forward," he said. "A lot of times there is a tendency to try to make these cases black and white. They are very rarely black and white; you very rarely have a Ray Rice video. There are allegations made, you try to sort through the facts and you try to make an informed decision. That is what we did here."
Mara said it might have been easier to part with Brown, but the organization is attempting to be fair to the kicker.
"I am trying to be fair to him as well. I think he is trying to do the right thing and he deserves an opportunity to show that he can do that," Mara said.