A onetime 3M Co. engineer has been sentenced to more than four years in prison for operating a long-running scheme that cost the Minnesota corporate giant more than $5 million.

David Beulke, 63, of Brookings, S.D., was sentenced to four years and three months in federal prison, to be followed by three years of supervised release. He also was ordered to pay $5.61 million in restitution to the Maplewood-based company.

"This was a large-scale scheme that was highly orchestrated and went undetected for many years," South Dakota U.S. Attorney Brendan Johnson said.

Beulke pleaded guilty on Dec. 10.

According to the case against him:

From Feb. 1, 1993, through Sept. 30, 2008, Beulke was an engineer at a 3M plant in Brookings that makes medical and surgical products. In that time, he created shell companies and presented them to his employer as legitimate vendors of specialized parts.

He arranged for 3M to order supposed parts from his shell companies, knowing that those orders were fraudulent, and kept the money for himself.

He initially deposited the money into various accounts, spent some on personal expenses and transferred a large amount into various investment and retirement accounts.

Working toward collecting the full restitution amount, the court ordered Beulke's attorney to turn over more than $1.22 million currently held on behalf of Beulke in an attorney trust account. The government previously had seized $2.48 million from retirement and investment accounts.