Investigators in Hudson, Wis., don't know why the 53-year-old owner of an auto body shop in West Fargo, N.D., drove 260 miles from home to rob two Hudson banks before killing himself in the parking lot of a Stillwater hospital.

Detectives from Wisconsin and North Dakota searched Alfred Josiah Knodle's Fargo home and West Fargo business Thursday, while in Wisconsin, Hudson police said Knodle seemed to be growing increasingly dangerous from his first suspected robbery, on Oct. 26, to the second on Wednesday.

Based on the surveillance videos, police believe Knodle committed both crimes.

"When you look at the first robbery videotape, he goes up to the cashier and demands money somewhat calmly. But in the second, he raises the gun and levels it at the clerk. He appears to be growing more aggressive, and the next one could have been worse," acting Hudson Police Chief Eric Atkinson told the St. Paul Pioneer Press.

Mitch Knodle said he was shocked to learn that investigators believed his brother was responsible for the robberies. He said Alfred Knodle occasionally drove to the Twin Cities for car auctions or to search for parts for his business, Alfred's Autobody and Sales shop.

"It's a major shock," Mitch Knodle said. "It doesn't make any sense to me at all. I don't know."

Alfred Knodle was not married and had no children, his brother said. According to court records in North Dakota, Knodle had filed for Chapter 7 bankruptcy in 1999.

On Wednesday, Knodle had allegedly walked into the Associated Bank in Hudson and robbed it at gunpoint before leading police into Minnesota. When cornered in the hospital parking lot, he shot himself.

Knodle shot himself in a white Mustang, a different vehicle than what was believed to be used in the Oct. 26 robbery at Citizens Bank in Hudson. But investigators on Thursday found the blue Buick they think was used in the first robbery, at Knodle's shop in West Fargo.

Law enforcement officials said it's rare for bank robbers to travel so far from home.

"They tend to come from the area, and often from that section of the metro area," FBI Special Agent Paul McCabe said.

McCabe said most bank robbers are fueling a drug addiction and spend little time plotting their robberies. The rest tend to need money for one reason or another, often because of a gambling addiction, he said.

Atkinson said investigators are looking into Knodle's business and any financial problems.

"We're trying to find a reason why, because he really doesn't have a criminal history," Atkinson said.