CHANDLER, Ariz.—The New England Patriots arrived Monday in Arizona for Super Bowl week with their owner, Robert Kraft, boldly taking the NFL to task while defending Coach Bill Belichick and quarterback Tom Brady.

Kraft spoke prior to Belichick or Brady at the team’s post-arrival news conference and expressed disappointment at the league’s handling of its investigation into the Patriots’ use of underinflated footballs in the first half of their victory over the Indianapolis Colts in the AFC championship game.

The owner said he believes the assertions by Belichick and Brady that they did nothing improper, and added that he expects an apology from the league if its investigation does not turn up evidence of intentional wrongdoing by the Patriots.

“I have spoken with Coach Belichick,” Kraft said, reading from a prepared statement as he stood in front of a room filled with media members at the Patriots’ hotel. “I have spoken with Tom Brady. I have taken the time to understand to the best of my abilities what goes on in the preparation of game-day footballs. And I want to make it clear that I believe unconditionally that the New England Patriots have done nothing inappropriate in this process or in violation of NFL rules.”

It is highly unusual for the owner of a team to speak at such a Super Bowl news conference, particularly on arrival day.

“Tom, Bill and I have been together for 15 years,” Kraft said. “They are my guys. They are part of my family. And Bill, Tom and I have had many difficult discussions over the years, and I have never known them to lie to me. That is why I am confident in saying what I just said. And it bothers me greatly that their reputations and integrity — and by association, that of our team — has been called into question this past week.”

Kraft said he welcomes the investigation being handled in part by attorney Ted Wells. He decried the “public discourse which has been driven by media leaks as opposed to actual data and facts,” and added: “Because of this, many jumped to conclusions and made strong accusations against our coach, quarterback and staff, questioning the integrity of all involved.

“If the Wells investigation is not able to definitively determine that our organization tampered with the air pressure in the footballs, I would expect and hope that the league would apologize to our entire team, and in particular Coach Belichick and Tom Brady, for what they have had to endure this past week,” Kraft said. “I am disappointed in the way this entire matter has been handled and reported upon. We expect hard facts, as opposed to circumstantial leaked evidence, to drive the conclusion of this investigation.”

The league did not immediately respond to a request for a reaction to Kraft’s comments.

Belichick stuck to what he’d said during a hastily called news conference Saturday in Foxborough, Mass., when he indicated he was done addressing the matter.

The coach deflected several questions Monday about the controversy.

“I have covered everything that I can cover in the previous week,” Belichick said. “And my attention is focused on the Seattle Seahawks.”

When Brady addressed reporters, he said that he knew little about Kraft’s remarks.

“I didn’t hear him,” Brady said. “They said as I was walking in he said some awfully nice things…. It’s a privilege to play for this team.”

Wells said in a written statement released earlier Monday by the league that he expected the investigation to last at least several more weeks, pushing a conclusion to the matter well past Sunday’s Super Bowl.

“We’ll see how this team reacts,” Brady said. “We’ve done a good job all season. I think we have a very mentally tough group…. As many of those things as we can put aside and deal with them at a later time, that’s what we’ll do.”