HOUSTON — An innocent mistake led to some frantic moments Monday night after Falcons offensive coordinator Kyle Shanahan’s backpack, which included the game plan for Super Bowl LI, went missing for nearly 30 minutes.

Shanahan had just finished his interview session at Super Bowl Opening Night at Minute Maid Park when he went to grab his backpack and return to the team hotel. Only it wasn’t there.

Was this some sort of subterfuge by the Patriots, who were sanctioned in 2007 for taping opponents’ defensive signals in the controversy known as Spygate? Was this a follow-up to Deflategate, when Tom Brady allegedly participated in a scheme to use purposely deflated footballs in the AFC Championship Game two years ago?

Nope. It was simply a case of mistaken backpack identity.

San Francisco-based sportswriter and columnist Art Spander, a regular contributor to Newsday, inadvertently took Shanahan’s backpack, thinking it was his own. Once Shanahan realized his was missing, he and Falcons officials went on a frantic search. Shanahan said to USA TODAY reporter Jarrett Bell, “I’ve got to find it.”

Spander’s backpack has numerous security tags (though without his name) on it, so Shanahan knew immediately it wasn’t his. Spander said Bell, an old friend, apparently recognized it was Spander’s. Bell knows his daughter Wendy, so he called her. Bell got Art’s cell phone number and gave it to a Falcons representative.

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“When I finally answered my phone, a disembodied voice ordered, ‘Get back to Shanahan. You have his game plan,’ ” said Spander, who was upstairs in a temporary press box. He quickly went down and returned the backpack to the Falcons representative.

“I wouldn’t say I gave it to him as much as he took it from me,” Spander told Newsday.

Early in the media session, Spander engaged in friendly banter with Shanahan, who will move to the Bay Area soon to become the coach of the 49ers, a team Spander has covered for decades.

“I walked up and cracked, ‘Enough of this nonsense. Get out to Santa Clara,’ ’’ Spander said, referring to the home of the 49ers’ training facility and stadium.

Shanahan laughed, and after about 15 minutes, Spander left with what he thought was his own backpack.

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The players and coaches already had departed while the search went on, and once the backpack was located, Shanahan texted Bell, “That would have been bad.”

Shanahan was not available at Tuesday’s media session, but is scheduled to speak to reporters Wednesday and Thursday.