BOSTON (AP) Now that authorities believe they have recovered the jersey stolen from Tom Brady's locker following the Patriots' Super Bowl win last month, the next step will be determining whether it is in fact the MVP quarterback's missing grass-stained garment.
So how exactly does that happen?
Old-fashioned detective work.
Experts in the sports memorabilia industry, including one that has worked directly with NFL teams, say it is a tedious process that involves comparing photos and videos that captured degradation to the jersey during the game. They also compare the jersey to team-issued serial numbers and other player-specific customizations that authentic jerseys typically have.
''Every jersey is like a fingerprint. No two jerseys are alike,'' said Barry Meisel, president of the MeiGray Group, which has authenticated game-worn sports memorabilia since 1997. ''They're hand-stitched, full of dirt, mud, helmet stains, turf skids and burns. When you look at jersey after a game it's unique.''
NFL spokesman Brian McCarthy declined Wednesday to discuss the authentication process due to security reasons, writing in an email only ''there are a number of procedures we have been using.'' The FBI also has not commented on the methods it is using.
Brady's jersey went missing from the Patriots' locker room after their Super Bowl win over the Atlanta Falcons Feb. 5, setting off an investigation that stretched from Boston to the Mexican border.
Working with U.S. investigators, Mexican authorities obtained a warrant to search property of Martin Mauricio Ortega, a tabloid journalist who colleagues say went to the game with a media credential, but bragged he was there as a fan. Authorities recovered the jersey, along with another Brady jersey that disappeared after the 2015 Super Bowl. A helmet belonging to a Denver Broncos player - possibly Von Miller - was also discovered. Ortega quit his job two days after the search, but has not been charged in the case and has not been located for comment.
MeiGray Group has authenticated jerseys for the NBA, NHL, USA Hockey and the NFL's Redskins and Chargers.
Most of the authentication Meisel's company is asked to perform involves a jersey coming from the hands of league official from a player in the locker room. But he said even in those cases, a process called photo matching is used.
In photo matching, an authenticator would utilize all the available photos and videos that captured images of the garment and compare stains, tears, and abrasions the garment undergoes over the course of a game.
His company was once asked by a collector to authenticate a jersey that an auction house was purporting to have been worn by Boston Bruins great Bobby Orr the night the Bruins captured the 1972 Stanley Cup.
Photos of him drinking from the Cup in the locker room after the game were used to prove it was real, based on comparisons of repair marks and stitching on the jersey.
In today's digital age, that process is a lot easier and more dependable.
''In the Brady jerseys case, you literally have millions of visuals for the Super Bowl,'' Meisel said.
There are also both league- and team-specific qualities that distinguish NFL game-worn gear. Meisel said he has never worked with the Patriots, but said teams he has worked with employ unique serial numbers that are placed on different parts of their uniforms.
Troy Kinunen, president of Memorabilia Evaluation and Research Services, said his company evaluated Babe Ruth's 1932 ''called shot'' jersey for a private collector. Authenticators used photos of old jerseys Ruth had worn to prove it was the real thing.
Kinunen said customizations set the jerseys apart from one a fan would buy at a store. His company maintains archives of those customizations.
Many NFL quarterbacks have their jerseys shortened or elasticized for comfort. And for the new Nike-made NFL jerseys, there is also a specific manner in which the lettering is sewn into the jersey, Kinunen said.
''The mesh holes create a pattern.you can examine application of how it's sewn on in conjunction with mesh holes,'' he said.
Major League Baseball has taken safeguarding game-used materials to an even higher level since beginning its authentication program with Authenticators, Inc. in 2001.
The group works with active and former law enforcement personnel to personally authenticate items on the spot. Those officials, who must pass background checks, on average have more than 25 years experience.
For MLB jerseys, an authenticator is stationed in the clubhouse and witnesses an item going from the player and into the laundry basket.
Once an item has been authenticated, it is affixed with a hologram and unique serial number that is searchable in the league's database located on MLB.com.
Kinunen said he expects the Brady incident to bring even more awareness to the authentication industry.
''It's a crazy story,'' he said. ''If I had to guess jerseys have been stolen out of locker rooms for 100 years. But the value wasn't there. Now it was a nationwide manhunt because of the value associated with it.''
Associated Press journalists Juan Lozano in Houston and Howie Rumberg in New York contributed to this report.
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