The Oakland Raiders will play the Patriots in Mexico City next season, and the Raiders and the Houston Texans played there in November, at Estadio Azteca, in what was the second regular-season N.F.L. game there. Ortega covered that game.
In recent years, some people who have received credentials have appeared at the Super Bowl simply to hang out or add to the spectacle, particularly on the Monday before the game, when the news media is allowed to interview players from both teams in what increasingly is a slickly produced television show. Some people with credentials dress in outrageous outfits and ask players embarrassing questions.
There was no sign on the website of La Prensa that Ortega wrote about the most recent Super Bowl or others, though he did write an article about the regular-season game in November.
Fox Sports, whose reporter Jay Glazer broke the news of the found Super Bowl LI jersey, broadcast a video that it said showed Ortega walking into the locker room and exiting with what looked like something under his shirt.
The parent company of La Prensa, OEM, one of the largest media companies in Mexico, said in a statement that Ortega resigned March 14, in a move company officials believed was related to health problems he had said close family members were having.
The statement said that “with total surprise and disappointment,” the company learned of the investigation and “energetically condemns” the behavior. It said officials had no knowledge of his involvement in the removal of the items. A person who answered the phone at La Prensa’s offices said there was no additional comment and hung up when asked for more information. There was no answer at OEM’s offices.
In a telephone interview, Brian McCarthy, a league spokesman, would not say where the jerseys had been found, or whether Ortega had brought them to the police after he was confronted. The F.B.I., he said, is continuing to investigate the matter.
Sgt. Scott Waite, a spokesman for the Glendale, Ariz., police department, said that no one from the Patriots or the N.F.L. had contacted the police after Brady’s jersey turned out to be missing two years ago because they “didn’t think it was foul play.”
A spokesman for the Broncos, Patrick Smyth, said the team had been in contact with the N.F.L.’s security team to determine whether the helmet recovered in Mexico belonged to Miller.
While the disappearance of Brady’s jersey two years ago and Miller’s helmet last year did not attract much attention, the theft of Brady’s jersey in February did.
Soon after the Patriots’ victory, Brady was seen on camera complaining that his jersey was gone.
“It was right here; I know exactly where I put it,” he could be overheard saying during a postgame celebration.
The next day, the lieutenant governor of Texas, Dan Patrick, asked the state police to help their counterparts in Houston find Brady’s jersey. At the time, it was unclear if it was misplaced or stolen.
Some auctioneers estimated that the jersey could fetch tens of thousands of dollars at auction. A police report in Houston put its value at $500,000. In an interview on Fox Business Network last month, the Patriots’ owner, Robert K. Kraft, compared the theft of Brady’s jersey to “taking a great Chagall or Picasso or something.”
Despite his visible irritation after the Super Bowl, Brady sought to shrug off the loss of the jersey the next day.
“Those are special ones to keep, you know, but what can you do?” he said after receiving a football-shaped trophy for being named the game’s most valuable player. “I’ll take the ring, and that’s good enough for me.”
Now, it appears, he will get back his jersey to go with the ring.
A larger question is whether the N.F.L., having been stung by the embarrassing theft, will alter reporters’ access to the locker room or teams, which traditionally has been seen as vital for obtaining details and comments unavailable to viewers at home. Jim Steeg, who ran the Super Bowl for the N.F.L. for more than 25 years, said the thefts were an inevitable result of an expanding postgame celebration.
In years past, only camera operators and a handful of media were on the field after the Super Bowl. Now, hundreds of reporters, as well as family and friends of the players, are on the field. This creates a festive atmosphere, but also additional headaches for security staff.
In the past, the players ran back to the locker rooms together and met privately with their coaches and team owners behind closed doors before reporters eventually would be let in, in a more organized fashion. Steeg recalled preventing the Rev. Jesse Jackson from entering the locker room after the Bears won the Super Bowl in 1986 because the team was meeting privately.
Unlike reporters of years ago, more now carry backpacks with their computers and other equipment that, in theory, could be used to stash equipment.
Steeg said that during his years running the Super Bowl, he had crews of security staff in both locker rooms around the clock to prevent any equipment from being stolen. But on game day, he said, it has become far more chaotic.
“It was almost inevitable that this happened,” Steeg said. “Now you literally had something taken not only out of the locker room, but out of a bag in the locker room.”
An earlier version of this article misidentified the Super Bowl after which Jesse Jackson was prevented from entering the locker room. It was after the Bears won the Super Bowl in 1986, not after the Raiders won in 1980.