The chairman of Minnesota's second-largest bank was abducted at gunpoint and forced to make a ransom demand from his car phone but escaped uninjured after being left alone in the woods, authorities said.

The search continued Tuesday for the lone gunman and the banker's Mercedes.First Bank System Chairman John Grundhofer was kidnapped Monday when he arrived at his office building. He escaped two hours later and called for help from a dairy farm in Wisconsin, just over the Minnesota line, authorities said.

Jeff Jamar, chief of the FBI's Minneapolis office, said the gunman approached Grundhofer in the bank's parking garage, forced him back into the car and told him to drive out of the city.

Authorities said Grundhofer called in a ransom demand to the bank about an hour later. The amount was not disclosed. The ransom was not paid.

The kidnapper "was prepared, well-planned. I believe he stalked him, knew who he was after," Jamar said.

Police Chief John Laux said a witness in the garage reported the kidnapping. Authorities gave few details on the sequence of events but said Grundhofer was left alone in the woods, freed himself and walked to a farm.

"He wasn't released, he escaped," Jamar said. "The person left him (and) told him he'd be back."