HELENA, Mont. -- The stocky man showed up in a basketball uniform for a game at Century High School in North Dakota. Players and coaches assumed he was a fan who had come with another team, so nobody objected when he began to pitch in around the bench.

"He helped lay out uniforms, got water. He even gave a couple of kids shoulder massages. Creepy stuff like that," said Jim Haussler, activities director for the Bismarck Public School District.

After the game was over, the man joined the winning team on the court and asked if he could get a piggyback ride. One bemused player gave it to him.

Security footage taken this month at Century High School in Bismarck, N.D., shows a man identified as Sherwin Shayegan of Bothell, Wash., known as the 'piggyback bandit.' AP Photo/Bismarck Schools

"He makes himself appear as if he's limited or handicapped. I think he plays an empathy card, so to speak," Haussler said. "We didn't realize what we were dealing with until several days later."

What they were dealing with the night of Feb. 4 was the Piggyback Bandit -- Sherwin Shayegan of Bothell, Wash., a 28-year-old man who ingratiates himself with high school sports teams, then hoists his 5-foot-8, 240-pound frame onto the backs of the student athletes.

Shayegan's antics stretch back to 2008 and had been mainly confined to Washington and Oregon. But since last fall, he has worked his way east to Montana, North Dakota and Minnesota, leaving a trail of befuddled athletes in his wake.

Shayegan has asked for piggybacks, attempted to pay for piggybacks and just sprung one upon an unsuspecting kid. He favors basketball games, but he also has leapt onto hockey, soccer and football players.

He has pretended to interview athletes for a term paper, acted as a team manager or just tried to blend in with the crowd for a piggyback payoff.

Why he does it is unclear, as is who came up with the "Piggyback Bandit" nickname that now follows him wherever he goes. Shayegan, contacted on his cellphone Tuesday, politely declined to speak of the piggyback rides until he could talk to an attorney.

"I'd prefer not to comment, if that's OK," he said.